diff --git a/registry/coder/modules/aws-region/README.md b/registry/coder/modules/aws-region/README.md
index c2527a306..ceb82f291 100644
--- a/registry/coder/modules/aws-region/README.md
+++ b/registry/coder/modules/aws-region/README.md
@@ -14,15 +14,15 @@ the region closest to them.
 Customize the preselected parameter value:
 
 ```tf
-module "aws-region" {
+module "aws_region" {
   count   = data.coder_workspace.me.start_count
   source  = "registry.coder.com/coder/aws-region/coder"
-  version = "1.0.31"
+  version = "1.1.0"
   default = "us-east-1"
 }
 
 provider "aws" {
-  region = module.aws_region.value
+  region = module.aws_region[0].value
 }
 ```
 
@@ -30,15 +30,62 @@ provider "aws" {
 
 ## Examples
 
+### Provision in the selected region's availability zone
+
+The `default_availability_zone` output resolves the selected region to a
+concrete zone (for example `us-east-1a`), so templates no longer have to guess
+it by appending a letter to the region ID:
+
+```tf
+module "aws_region" {
+  source  = "registry.coder.com/coder/aws-region/coder"
+  version = "1.1.0"
+  default = "us-east-1"
+}
+
+provider "aws" {
+  region = module.aws_region.value
+}
+
+resource "aws_instance" "dev" {
+  ami               = data.aws_ami.ubuntu.id
+  instance_type     = "t3.micro"
+  availability_zone = module.aws_region.default_availability_zone
+  # ...
+}
+```
+
+### Use the outputs without a parameter
+
+Set `create_parameter = false` to skip the region picker and pin a region
+yourself, while still using the module's outputs (for example
+`default_availability_zone` or the full `regions` catalog):
+
+```tf
+module "aws_region" {
+  source           = "registry.coder.com/coder/aws-region/coder"
+  version          = "1.1.0"
+  create_parameter = false
+  default          = "us-east-1"
+}
+
+provider "aws" {
+  region = module.aws_region.value # "us-east-1"
+}
+
+# module.aws_region.default_availability_zone => "us-east-1a"
+# module.aws_region.regions                   => full catalog keyed by region ID
+```
+
 ### Customize regions
 
 Change the display name and icon for a region using the corresponding maps:
 
 ```tf
-module "aws-region" {
+module "aws_region" {
   count   = data.coder_workspace.me.start_count
   source  = "registry.coder.com/coder/aws-region/coder"
-  version = "1.0.31"
+  version = "1.1.0"
   default = "ap-south-1"
 
   custom_names = {
@@ -51,7 +98,7 @@ module "aws-region" {
 }
 
 provider "aws" {
-  region = module.aws_region.value
+  region = module.aws_region[0].value
 }
 ```
 
@@ -62,20 +109,68 @@ provider "aws" {
 Hide the Asia Pacific regions Seoul and Osaka:
 
 ```tf
-module "aws-region" {
+module "aws_region" {
   count   = data.coder_workspace.me.start_count
   source  = "registry.coder.com/coder/aws-region/coder"
-  version = "1.0.31"
+  version = "1.1.0"
   exclude = ["ap-northeast-2", "ap-northeast-3"]
 }
 
 provider "aws" {
-  region = module.aws_region.value
+  region = module.aws_region[0].value
 }
 ```
 
 ![AWS Exclude](../../.images/aws-exclude.png)
 
+## Outputs
+
+| Output                      | Description                                                                          |
+| --------------------------- | ------------------------------------------------------------------------------------ |
+| `value`                     | The ID of the selected region, e.g. `us-east-1`.                                     |
+| `default_availability_zone` | The default availability zone for the selected region, e.g. `us-east-1a`.            |
+| `regions`                   | Every region keyed by ID, each with `name`, `icon`, and `default_availability_zone`. |
+
+## Updating regions.json
+
+`regions.json` is a generated catalog of region IDs, display names, and flag
+icons, so the module needs no AWS provider or credentials at plan time.
+Terraform only reads the file; all the flag logic lives in the script below.
+
+Regenerate the whole file from AWS with the AWS CLI (any credentials) and `jq`,
+run from this module's directory. Names and country codes come from the public
+`global-infrastructure` SSM parameters in `us-east-1`:
+
+```bash
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Two-letter country code -> Coder flag emoji asset (regional indicator pair).
+icon() {
+  local a b
+  a=$(printf '%x' $((0x1f1e6 + $(printf '%d' "'${1:0:1}") - 0x61)))
+  b=$(printf '%x' $((0x1f1e6 + $(printf '%d' "'${1:1:1}") - 0x61)))
+  printf '/emojis/%s-%s.png' "$a" "$b"
+}
+
+for region in $(aws ec2 describe-regions --all-regions \
+  --query 'Regions[].RegionName' --output text | tr '\t' '\n' | sort); do
+  name=$(aws ssm get-parameter --region us-east-1 \
+    --name "/aws/service/global-infrastructure/regions/$region/longName" \
+    --query Parameter.Value --output text)
+  # European regions share the EU flag; every other region uses its country flag.
+  if [[ $region == eu-* ]]; then
+    country=eu
+  else
+    country=$(aws ssm get-parameter --region us-east-1 \
+      --name "/aws/service/global-infrastructure/regions/$region/geolocationCountry" \
+      --query Parameter.Value --output text | tr '[:upper:]' '[:lower:]')
+  fi
+  jq -n --arg value "$region" --arg name "$name" --arg icon "$(icon "$country")" \
+    '{$value, $name, $icon}'
+done | jq -s '.' > regions.json
+```
+
 ## Related templates
 
 For a complete AWS EC2 template, see the following examples in the [Coder Registry](https://registry.coder.com/).
diff --git a/registry/coder/modules/aws-region/main.test.ts b/registry/coder/modules/aws-region/main.test.ts
deleted file mode 100644
index b7768cf2e..000000000
--- a/registry/coder/modules/aws-region/main.test.ts
+++ /dev/null
@@ -1,33 +0,0 @@
-import { describe, expect, it } from "bun:test";
-import {
-  runTerraformApply,
-  runTerraformInit,
-  testRequiredVariables,
-} from "~test";
-
-describe("aws-region", async () => {
-  await runTerraformInit(import.meta.dir);
-
-  testRequiredVariables(import.meta.dir, {});
-
-  it("default output", async () => {
-    const state = await runTerraformApply(import.meta.dir, {});
-    expect(state.outputs.value.value).toBe("");
-  });
-
-  it("customized default", async () => {
-    const state = await runTerraformApply(import.meta.dir, {
-      default: "us-west-2",
-    });
-    expect(state.outputs.value.value).toBe("us-west-2");
-  });
-
-  it("set custom order for coder_parameter", async () => {
-    const order = 99;
-    const state = await runTerraformApply(import.meta.dir, {
-      coder_parameter_order: order.toString(),
-    });
-    expect(state.resources).toHaveLength(1);
-    expect(state.resources[0].instances[0].attributes.order).toBe(order);
-  });
-});
diff --git a/registry/coder/modules/aws-region/main.tf b/registry/coder/modules/aws-region/main.tf
index 12a01fe76..3edd76134 100644
--- a/registry/coder/modules/aws-region/main.tf
+++ b/registry/coder/modules/aws-region/main.tf
@@ -22,9 +22,14 @@ variable "description" {
 }
 
 variable "default" {
-  default     = ""
-  description = "The default region to use if no region is specified."
+  default     = null
+  description = "The default region to preselect, e.g. \"us-east-1\". Leave unset for no preselection; also used as the selected region when create_parameter is false."
   type        = string
+
+  validation {
+    condition     = var.default == null || can(regex("^[a-z]{2}-[a-z]+-[0-9]+$", var.default))
+    error_message = "default must be null or a valid AWS region ID, e.g. \"us-east-1\"."
+  }
 }
 
 variable "mutable" {
@@ -49,6 +54,11 @@ variable "exclude" {
   default     = []
   description = "A list of region IDs to exclude."
   type        = list(string)
+
+  validation {
+    condition     = alltrue([for region in var.exclude : can(regex("^[a-z]{2}-[a-z]+-[0-9]+$", region))])
+    error_message = "exclude must contain valid AWS region IDs, e.g. \"ap-northeast-2\"."
+  }
 }
 
 variable "coder_parameter_order" {
@@ -57,143 +67,59 @@ variable "coder_parameter_order" {
   default     = null
 }
 
+variable "create_parameter" {
+  type        = bool
+  description = "Whether to create the coder_parameter. Set to false to skip the region picker and use the module only for its outputs, e.g. the regions catalog or a default_availability_zone for a fixed default region."
+  default     = true
+}
+
 locals {
-  # This is a static list because the regions don't change _that_
-  # frequently and including the `aws_regions` data source requires
-  # the provider, which requires a region.
-  regions = {
-    "af-south-1" = {
-      name = "Africa (Cape Town)"
-      icon = "/emojis/1f1ff-1f1e6.png"
-    }
-    "ap-east-1" = {
-      name = "Asia Pacific (Hong Kong)"
-      icon = "/emojis/1f1ed-1f1f0.png"
-    }
-    "ap-northeast-1" = {
-      name = "Asia Pacific (Tokyo)"
-      icon = "/emojis/1f1ef-1f1f5.png"
-    }
-    "ap-northeast-2" = {
-      name = "Asia Pacific (Seoul)"
-      icon = "/emojis/1f1f0-1f1f7.png"
-    }
-    "ap-northeast-3" = {
-      name = "Asia Pacific (Osaka)"
-      icon = "/emojis/1f1ef-1f1f5.png"
-    }
-    "ap-south-1" = {
-      name = "Asia Pacific (Mumbai)"
-      icon = "/emojis/1f1ee-1f1f3.png"
-    }
-    "ap-south-2" = {
-      name = "Asia Pacific (Hyderabad)"
-      icon = "/emojis/1f1ee-1f1f3.png"
-    }
-    "ap-southeast-1" = {
-      name = "Asia Pacific (Singapore)"
-      icon = "/emojis/1f1f8-1f1ec.png"
-    }
-    "ap-southeast-2" = {
-      name = "Asia Pacific (Sydney)"
-      icon = "/emojis/1f1e6-1f1fa.png"
-    }
-    "ap-southeast-3" = {
-      name = "Asia Pacific (Jakarta)"
-      icon = "/emojis/1f1ee-1f1e9.png"
-    }
-    "ap-southeast-4" = {
-      name = "Asia Pacific (Melbourne)"
-      icon = "/emojis/1f1e6-1f1fa.png"
-    }
-    "ca-central-1" = {
-      name = "Canada (Central)"
-      icon = "/emojis/1f1e8-1f1e6.png"
-    }
-    "ca-west-1" = {
-      name = "Canada West (Calgary)"
-      icon = "/emojis/1f1e8-1f1e6.png"
-    }
-    "eu-central-1" = {
-      name = "EU (Frankfurt)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-central-2" = {
-      name = "Europe (Zurich)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-north-1" = {
-      name = "EU (Stockholm)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-south-1" = {
-      name = "Europe (Milan)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-south-2" = {
-      name = "Europe (Spain)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-west-1" = {
-      name = "EU (Ireland)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-west-2" = {
-      name = "EU (London)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "eu-west-3" = {
-      name = "EU (Paris)"
-      icon = "/emojis/1f1ea-1f1fa.png"
-    }
-    "il-central-1" = {
-      name = "Israel (Tel Aviv)"
-      icon = "/emojis/1f1ee-1f1f1.png"
-    }
-    "me-south-1" = {
-      name = "Middle East (Bahrain)"
-      icon = "/emojis/1f1e7-1f1ed.png"
-    }
-    "sa-east-1" = {
-      name = "South America (São Paulo)"
-      icon = "/emojis/1f1e7-1f1f7.png"
-    }
-    "us-east-1" = {
-      name = "US East (N. Virginia)"
-      icon = "/emojis/1f1fa-1f1f8.png"
-    }
-    "us-east-2" = {
-      name = "US East (Ohio)"
-      icon = "/emojis/1f1fa-1f1f8.png"
-    }
-    "us-west-1" = {
-      name = "US West (N. California)"
-      icon = "/emojis/1f1fa-1f1f8.png"
-    }
-    "us-west-2" = {
-      name = "US West (Oregon)"
-      icon = "/emojis/1f1fa-1f1f8.png"
+  # Read regions.json with a fallback: Terraform resolves file() from the root
+  # module, but Coder's dynamic parameters preview resolves it from this module's
+  # directory, so neither path works on its own.
+  regions = jsondecode(try(file("${path.module}/regions.json"), file("regions.json")))
+
+  regions_by_id = {
+    for region in local.regions : region.value => {
+      value                     = region.value
+      name                      = region.name
+      icon                      = region.icon
+      default_availability_zone = "${region.value}a"
     }
   }
+
+  selected_region = var.create_parameter ? one(data.coder_parameter.region[*].value) : var.default
 }
 
 data "coder_parameter" "region" {
+  count        = var.create_parameter ? 1 : 0
   name         = "aws_region"
   display_name = var.display_name
   description  = var.description
-  default      = var.default == "" ? null : var.default
+  default      = var.default
   order        = var.coder_parameter_order
   mutable      = var.mutable
   dynamic "option" {
-    for_each = { for k, v in local.regions : k => v if !(contains(var.exclude, k)) }
+    for_each = [for region in local.regions : region if !contains(var.exclude, region.value)]
     content {
-      name  = try(var.custom_names[option.key], option.value.name)
-      icon  = try(var.custom_icons[option.key], option.value.icon)
-      value = option.key
+      name  = try(var.custom_names[option.value.value], option.value.name)
+      icon  = try(var.custom_icons[option.value.value], option.value.icon)
+      value = option.value.value
     }
   }
 }
 
 output "value" {
-  value = data.coder_parameter.region.value
-}
\ No newline at end of file
+  description = "The ID of the selected AWS region, e.g. \"us-east-1\". Falls back to var.default when create_parameter is false."
+  value       = local.selected_region
+}
+
+output "default_availability_zone" {
+  description = "The default availability zone for the selected region, e.g. \"us-east-1a\". Empty when no region is selected."
+  value       = try(local.regions_by_id[local.selected_region].default_availability_zone, "")
+}
+
+output "regions" {
+  description = "All AWS regions keyed by region ID, each with name, icon, and default_availability_zone."
+  value       = local.regions_by_id
+}
diff --git a/registry/coder/modules/aws-region/main.tftest.hcl b/registry/coder/modules/aws-region/main.tftest.hcl
new file mode 100644
index 000000000..781439a65
--- /dev/null
+++ b/registry/coder/modules/aws-region/main.tftest.hcl
@@ -0,0 +1,136 @@
+run "parameter_name" {
+  command = plan
+
+  assert {
+    condition     = data.coder_parameter.region[0].name == "aws_region"
+    error_message = "Parameter name should be aws_region"
+  }
+}
+
+run "custom_order" {
+  command = plan
+
+  variables {
+    coder_parameter_order = 99
+  }
+
+  assert {
+    condition     = data.coder_parameter.region[0].order == 99
+    error_message = "coder_parameter_order should propagate to the parameter order"
+  }
+}
+
+run "all_regions_are_options" {
+  command = plan
+
+  assert {
+    condition     = length(data.coder_parameter.region[0].option) == length(local.regions)
+    error_message = "Every catalog region should be rendered as a selectable option"
+  }
+}
+
+run "default_output_empty" {
+  command = apply
+
+  assert {
+    condition     = output.value == "" && output.default_availability_zone == ""
+    error_message = "With no default and no selection, value and default_availability_zone should be empty"
+  }
+}
+
+run "custom_default" {
+  command = apply
+
+  variables {
+    default = "us-west-2"
+  }
+
+  assert {
+    condition     = output.value == "us-west-2" && output.default_availability_zone == "us-west-2a"
+    error_message = "value and default_availability_zone should follow the configured default"
+  }
+}
+
+run "regions_output_exposes_catalog" {
+  command = plan
+
+  assert {
+    condition     = length(output.regions) == length(local.regions)
+    error_message = "regions output should expose every catalog entry keyed by ID"
+  }
+
+  assert {
+    condition = (
+      output.regions["ap-northeast-1"].name == "Asia Pacific (Tokyo)" &&
+      output.regions["ap-northeast-1"].icon == "/emojis/1f1ef-1f1f5.png" &&
+      output.regions["ap-northeast-1"].default_availability_zone == "ap-northeast-1a"
+    )
+    error_message = "regions entries should expose name, icon, and default_availability_zone"
+  }
+}
+
+run "exclude_removes_option" {
+  command = apply
+
+  variables {
+    exclude = ["ap-northeast-2", "ap-northeast-3"]
+  }
+
+  assert {
+    condition = (
+      !contains([for o in data.coder_parameter.region[0].option : o.value], "ap-northeast-2") &&
+      !contains([for o in data.coder_parameter.region[0].option : o.value], "ap-northeast-3")
+    )
+    error_message = "Excluded regions should not appear as options"
+  }
+}
+
+run "custom_names_and_icons_override" {
+  command = apply
+
+  variables {
+    custom_names = {
+      "ap-south-1" = "Awesome Mumbai!"
+    }
+    custom_icons = {
+      "ap-south-1" = "/emojis/1f33a.png"
+    }
+  }
+
+  assert {
+    condition     = length([for o in data.coder_parameter.region[0].option : o if o.value == "ap-south-1" && o.name == "Awesome Mumbai!" && o.icon == "/emojis/1f33a.png"]) == 1
+    error_message = "custom_names and custom_icons should override the defaults for a region"
+  }
+}
+
+run "outputs_without_parameter" {
+  command = apply
+
+  variables {
+    create_parameter = false
+    default          = "eu-west-1"
+  }
+
+  assert {
+    condition     = length(data.coder_parameter.region) == 0
+    error_message = "create_parameter = false should not create the coder_parameter"
+  }
+
+  assert {
+    condition     = output.value == "eu-west-1" && output.default_availability_zone == "eu-west-1a"
+    error_message = "With create_parameter = false, outputs should fall back to var.default"
+  }
+}
+
+run "no_parameter_and_no_default" {
+  command = apply
+
+  variables {
+    create_parameter = false
+  }
+
+  assert {
+    condition     = output.value == null && output.default_availability_zone == ""
+    error_message = "With no parameter and no default, value is null and default_availability_zone is empty"
+  }
+}
diff --git a/registry/coder/modules/aws-region/regions.json b/registry/coder/modules/aws-region/regions.json
new file mode 100644
index 000000000..7ae421da6
--- /dev/null
+++ b/registry/coder/modules/aws-region/regions.json
@@ -0,0 +1,142 @@
+[
+  {
+    "value": "af-south-1",
+    "name": "Africa (Cape Town)",
+    "icon": "/emojis/1f1ff-1f1e6.png"
+  },
+  {
+    "value": "ap-east-1",
+    "name": "Asia Pacific (Hong Kong)",
+    "icon": "/emojis/1f1ed-1f1f0.png"
+  },
+  {
+    "value": "ap-northeast-1",
+    "name": "Asia Pacific (Tokyo)",
+    "icon": "/emojis/1f1ef-1f1f5.png"
+  },
+  {
+    "value": "ap-northeast-2",
+    "name": "Asia Pacific (Seoul)",
+    "icon": "/emojis/1f1f0-1f1f7.png"
+  },
+  {
+    "value": "ap-northeast-3",
+    "name": "Asia Pacific (Osaka)",
+    "icon": "/emojis/1f1ef-1f1f5.png"
+  },
+  {
+    "value": "ap-south-1",
+    "name": "Asia Pacific (Mumbai)",
+    "icon": "/emojis/1f1ee-1f1f3.png"
+  },
+  {
+    "value": "ap-south-2",
+    "name": "Asia Pacific (Hyderabad)",
+    "icon": "/emojis/1f1ee-1f1f3.png"
+  },
+  {
+    "value": "ap-southeast-1",
+    "name": "Asia Pacific (Singapore)",
+    "icon": "/emojis/1f1f8-1f1ec.png"
+  },
+  {
+    "value": "ap-southeast-2",
+    "name": "Asia Pacific (Sydney)",
+    "icon": "/emojis/1f1e6-1f1fa.png"
+  },
+  {
+    "value": "ap-southeast-3",
+    "name": "Asia Pacific (Jakarta)",
+    "icon": "/emojis/1f1ee-1f1e9.png"
+  },
+  {
+    "value": "ap-southeast-4",
+    "name": "Asia Pacific (Melbourne)",
+    "icon": "/emojis/1f1e6-1f1fa.png"
+  },
+  {
+    "value": "ca-central-1",
+    "name": "Canada (Central)",
+    "icon": "/emojis/1f1e8-1f1e6.png"
+  },
+  {
+    "value": "ca-west-1",
+    "name": "Canada West (Calgary)",
+    "icon": "/emojis/1f1e8-1f1e6.png"
+  },
+  {
+    "value": "eu-central-1",
+    "name": "Europe (Frankfurt)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-central-2",
+    "name": "Europe (Zurich)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-north-1",
+    "name": "Europe (Stockholm)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-south-1",
+    "name": "Europe (Milan)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-south-2",
+    "name": "Europe (Spain)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-west-1",
+    "name": "Europe (Ireland)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-west-2",
+    "name": "Europe (London)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "eu-west-3",
+    "name": "Europe (Paris)",
+    "icon": "/emojis/1f1ea-1f1fa.png"
+  },
+  {
+    "value": "il-central-1",
+    "name": "Israel (Tel Aviv)",
+    "icon": "/emojis/1f1ee-1f1f1.png"
+  },
+  {
+    "value": "me-south-1",
+    "name": "Middle East (Bahrain)",
+    "icon": "/emojis/1f1e7-1f1ed.png"
+  },
+  {
+    "value": "sa-east-1",
+    "name": "South America (São Paulo)",
+    "icon": "/emojis/1f1e7-1f1f7.png"
+  },
+  {
+    "value": "us-east-1",
+    "name": "US East (N. Virginia)",
+    "icon": "/emojis/1f1fa-1f1f8.png"
+  },
+  {
+    "value": "us-east-2",
+    "name": "US East (Ohio)",
+    "icon": "/emojis/1f1fa-1f1f8.png"
+  },
+  {
+    "value": "us-west-1",
+    "name": "US West (N. California)",
+    "icon": "/emojis/1f1fa-1f1f8.png"
+  },
+  {
+    "value": "us-west-2",
+    "name": "US West (Oregon)",
+    "icon": "/emojis/1f1fa-1f1f8.png"
+  }
+]