diff --git a/apps/server/src/routes/rpc/handlers/monitor/validators.test.ts b/apps/server/src/routes/rpc/handlers/monitor/validators.test.ts
index d52bf70e..1d3546a0 100644
--- a/apps/server/src/routes/rpc/handlers/monitor/validators.test.ts
+++ b/apps/server/src/routes/rpc/handlers/monitor/validators.test.ts
@@ -165,10 +165,10 @@ describe("validateCommonMonitorFields", () => {
   test("drops an unspecified region instead of rejecting it", () => {
     // Documents current behaviour, which is weaker than it looks:
     // `regionsToStrings` filters unmapped enum values to "", so the
-    // "Invalid regions" error below can never fire on the RPC path —
-    // every proto Region that maps to a non-empty string is in
-    // AVAILABLE_REGIONS. An unknown region is silently dropped and the
-    // monitor is created with fewer regions than the caller asked for.
+    // "Invalid regions" error can never fire on the RPC path — every proto
+    // Region maps either to AVAILABLE_REGIONS or to a deprecated region,
+    // which the deprecation check rejects first. An unknown region is
+    // silently dropped and the monitor is created with fewer regions.
     expect(() =>
       validateCommonMonitorFields({ regions: [Region.UNSPECIFIED] }),
     ).not.toThrow();
diff --git a/packages/db/script/region-migration.test.ts b/packages/db/script/region-migration.test.ts
index 29981071..38c6bc26 100644
--- a/packages/db/script/region-migration.test.ts
+++ b/packages/db/script/region-migration.test.ts
@@ -3,7 +3,7 @@ import { beforeEach, describe, test } from "@std/testing/bdd";
 import type { z } from "zod";
 
 import type { monitorRegionSchema } from "../src/schema/constants";
-import { updateRegion } from "./region-migration";
+import { applyRegionRemaps, updateRegion } from "./region-migration";
 
 // Import the types we need
 
@@ -59,6 +59,17 @@ describe("updateRegion", () => {
       expect(regions).toEqual(["ams", "sin"]);
     });
 
+    test("should replace every bom when it is listed twice", () => {
+      const regions: z.infer<typeof monitorRegionSchema>[] = [
+        "bom",
+        "ams",
+        "bom",
+      ];
+      applyRegionRemaps(regions);
+
+      expect(regions).toEqual(["sin", "ams"]);
+    });
+
     test("should drop bom when sin is already selected", () => {
       const regions: z.infer<typeof monitorRegionSchema>[] = [
         "bom",
@@ -181,38 +192,14 @@ describe("updateRegion", () => {
           "yul",
           "yyz",
         ] as z.infer<typeof monitorRegionSchema>[];
-        // Asia Pacific
-        updateRegion("hkg", "sin", newRegions);
-
-        // North America
-        updateRegion("atl", "dfw", newRegions);
-        updateRegion("mia", "dfw", newRegions);
-        updateRegion("gdl", "dfw", newRegions);
-        updateRegion("qro", "dfw", newRegions);
-        updateRegion("bos", "ewr", newRegions);
-        updateRegion("phx", "lax", newRegions);
-        updateRegion("sea", "sjc", newRegions);
-        updateRegion("yul", "yyz", newRegions);
-
-        // Europe
-        updateRegion("waw", "ams", newRegions);
-        updateRegion("mad", "cdg", newRegions);
-        updateRegion("otp", "fra", newRegions);
-
-        // South America
-        updateRegion("bog", "gru", newRegions);
-        updateRegion("gig", "gru", newRegions);
-        updateRegion("scl", "gru", newRegions);
-        updateRegion("eze", "gru", newRegions);
+        applyRegionRemaps(newRegions);
 
         // Should be the same reference (mutated)
 
         expect(newRegions).toEqual([
           "ams",
           "arn",
-          "bom",
           "cdg",
-          "den",
           "dfw",
           "ewr",
           "fra",
diff --git a/packages/db/script/region-migration.ts b/packages/db/script/region-migration.ts
index 0e96cfbd..b4521bf2 100644
--- a/packages/db/script/region-migration.ts
+++ b/packages/db/script/region-migration.ts
@@ -4,6 +4,42 @@ import { db, eq, schema } from "../src";
 import { selectMonitorSchema } from "../src/schema";
 import type { monitorRegionSchema } from "../src/schema/constants";
 
+type MonitorRegion = z.infer<typeof monitorRegionSchema>;
+
+// Every deprecated region and its replacement. Earlier entries already ran;
+// they stay because re-applying them is a no-op.
+export const REGION_REMAPS: ReadonlyArray<[MonitorRegion, MonitorRegion]> = [
+  // Asia Pacific
+  ["hkg", "sin"],
+  ["bom", "sin"],
+  // North America
+  ["atl", "dfw"],
+  ["mia", "dfw"],
+  ["gdl", "dfw"],
+  ["qro", "dfw"],
+  ["bos", "ewr"],
+  ["phx", "lax"],
+  ["sea", "sjc"],
+  ["yul", "yyz"],
+  ["den", "dfw"],
+  // Europe
+  ["waw", "ams"],
+  ["mad", "cdg"],
+  ["otp", "fra"],
+  // South America
+  ["bog", "gru"],
+  ["gig", "gru"],
+  ["scl", "gru"],
+  ["eze", "gru"],
+];
+
+export function applyRegionRemaps(regions: MonitorRegion[]) {
+  for (const [from, to] of REGION_REMAPS) {
+    // `updateRegion` handles one occurrence; a region can be listed twice.
+    while (regions.includes(from)) updateRegion(from, to, regions);
+  }
+}
+
 // Only run against the DB when executed directly, not when imported by tests.
 if (import.meta.main) {
   const rawMonitors = await db.select().from(schema.monitor);
@@ -11,8 +47,7 @@ if (import.meta.main) {
   const monitors = z.array(selectMonitorSchema).parse(rawMonitors);
   for (const monitor of monitors) {
     const regions = monitor.regions.slice();
-    // Asia Pacific
-    updateRegion("bom", "sin", regions);
+    applyRegionRemaps(regions);
     const newRegions = regions.join(",");
     if (newRegions === monitor.regions.join(",")) continue;
     await db
diff --git a/packages/db/src/seed/limits.ts b/packages/db/src/seed/limits.ts
index 245a66fe..8bf74b21 100644
--- a/packages/db/src/seed/limits.ts
+++ b/packages/db/src/seed/limits.ts
@@ -29,7 +29,6 @@ export const TEAM_WORKSPACE_LIMITS = JSON.stringify({
     "arn",
     "atl",
     "bog",
-    "bom",
     "bos",
     "cdg",
     "den",
diff --git a/packages/importers/package.json b/packages/importers/package.json
index 6d960986..fc2ce10a 100644
--- a/packages/importers/package.json
+++ b/packages/importers/package.json
@@ -25,6 +25,7 @@
     "zod": "catalog:"
   },
   "devDependencies": {
+    "@openstatus/regions": "workspace:*",
     "@openstatus/tsconfig": "workspace:*",
     "@std/expect": "jsr:^1.0.19",
     "@std/testing": "jsr:^1.0.19",
diff --git a/packages/importers/src/providers/betterstack/mapper.test.ts b/packages/importers/src/providers/betterstack/mapper.test.ts
index 1d805155..028d01bc 100644
--- a/packages/importers/src/providers/betterstack/mapper.test.ts
+++ b/packages/importers/src/providers/betterstack/mapper.test.ts
@@ -1,3 +1,4 @@
+import { regionDict } from "@openstatus/regions";
 import { expect } from "@std/expect";
 import { describe, test } from "@std/testing/bdd";
 
@@ -28,6 +29,7 @@ import {
   mapResource,
   mapSection,
   mapStatusPage,
+  REGION_MAP,
 } from "./mapper";
 
 describe("mapFrequency", () => {
@@ -62,6 +64,17 @@ describe("mapRegions", () => {
     expect(mapRegions(["us", "eu", "as", "au"])).toBe("iad,fra,sin,syd");
   });
 
+  test("only targets regions that are still available", () => {
+    for (const [location, region] of Object.entries(REGION_MAP)) {
+      const info = regionDict[region as keyof typeof regionDict];
+      expect({ location, region, deprecated: info?.deprecated }).toEqual({
+        location,
+        region,
+        deprecated: false,
+      });
+    }
+  });
+
   test("returns default for unknown regions", () => {
     expect(mapRegions([])).toBe("iad");
     expect(mapRegions(["unknown"])).toBe("iad");
diff --git a/packages/importers/src/providers/betterstack/mapper.ts b/packages/importers/src/providers/betterstack/mapper.ts
index 4701bdb0..4c14bfad 100644
--- a/packages/importers/src/providers/betterstack/mapper.ts
+++ b/packages/importers/src/providers/betterstack/mapper.ts
@@ -27,7 +27,8 @@ const FREQUENCY_MAP: Record<number, string> = {
   3600: "1h",
 };
 
-const REGION_MAP: Record<string, string> = {
+// Imports write regions unvalidated, so every target must be non-deprecated.
+export const REGION_MAP: Record<string, string> = {
   us: "iad",
   eu: "fra",
   as: "sin",
diff --git a/packages/importers/src/providers/checkly/mapper.test.ts b/packages/importers/src/providers/checkly/mapper.test.ts
index a73f4ce4..f7123a6b 100644
--- a/packages/importers/src/providers/checkly/mapper.test.ts
+++ b/packages/importers/src/providers/checkly/mapper.test.ts
@@ -1,3 +1,4 @@
+import { regionDict } from "@openstatus/regions";
 import { expect } from "@std/expect";
 import { describe, test } from "@std/testing/bdd";
 
@@ -18,6 +19,7 @@ import {
   mapPage,
   mapRegions,
   mapService,
+  REGION_MAP,
 } from "./mapper";
 
 describe("mapCheckType", () => {
@@ -57,6 +59,23 @@ describe("mapRegions", () => {
     expect(mapRegions(["us-east-1", "eu-west-1"])).toBe("iad,lhr");
   });
 
+  test("only targets regions that are still available", () => {
+    for (const [location, region] of Object.entries(REGION_MAP)) {
+      const info = regionDict[region as keyof typeof regionDict];
+      expect({ location, region, deprecated: info?.deprecated }).toEqual({
+        location,
+        region,
+        deprecated: false,
+      });
+    }
+  });
+
+  test("maps deprecated targets to their replacements", () => {
+    expect(mapRegions(["ap-south-1", "us-west-2", "ca-central-1"])).toBe(
+      "sin,sjc,yyz",
+    );
+  });
+
   test("dedupes collapsed regions", () => {
     expect(mapRegions(["us-east-1", "us-east-2"])).toBe("iad");
   });
diff --git a/packages/importers/src/providers/checkly/mapper.ts b/packages/importers/src/providers/checkly/mapper.ts
index 58cfbfe1..46da5d97 100644
--- a/packages/importers/src/providers/checkly/mapper.ts
+++ b/packages/importers/src/providers/checkly/mapper.ts
@@ -53,19 +53,20 @@ export function mapFrequency(minutes: number): string {
   return FREQUENCY_MAP[closest] ?? "10m";
 }
 
-// AWS region codes (Checkly locations) → Fly regions (OpenStatus).
-const REGION_MAP: Record<string, string> = {
+// AWS region codes (Checkly locations) → Fly regions (OpenStatus). Imports
+// write regions unvalidated, so every target must be a non-deprecated region.
+export const REGION_MAP: Record<string, string> = {
   "us-east-1": "iad",
   "us-east-2": "iad",
   "us-west-1": "sjc",
-  "us-west-2": "sea",
-  "ca-central-1": "yul",
+  "us-west-2": "sjc",
+  "ca-central-1": "yyz",
   "eu-west-1": "lhr",
   "eu-west-2": "lhr",
   "eu-west-3": "cdg",
   "eu-central-1": "fra",
   "eu-north-1": "arn",
-  "ap-south-1": "bom",
+  "ap-south-1": "sin",
   "ap-southeast-1": "sin",
   "ap-southeast-2": "syd",
   "ap-northeast-1": "nrt",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 2753dcee..98948c25 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -2320,6 +2320,9 @@ importers:
         specifier: 'catalog:'
         version: 4.6.5
     devDependencies:
+      '@openstatus/regions':
+        specifier: workspace:*
+        version: link:../regions
       '@openstatus/tsconfig':
         specifier: workspace:*
         version: link:../tsconfig