diff --git a/packages/@aws-cdk/aws-ec2-alpha/lib/ipam.ts b/packages/@aws-cdk/aws-ec2-alpha/lib/ipam.ts
index 4e27d67183c90..2d84830103727 100644
--- a/packages/@aws-cdk/aws-ec2-alpha/lib/ipam.ts
+++ b/packages/@aws-cdk/aws-ec2-alpha/lib/ipam.ts
@@ -573,13 +573,17 @@ function createIpamPool(
   poolOptions: PoolOptions,
   scopeId: string,
 ): IpamPool {
-  const isLocaleInOperatingRegions = scopeOptions.ipamOperatingRegions
-    ? scopeOptions.ipamOperatingRegions.map(region => ({ regionName: region }))
-      .some(region => region.regionName === poolOptions.locale)
-    : false;
-
-  if (!isLocaleInOperatingRegions) {
-    throw new Error(`The provided locale '${poolOptions.locale}' is not in the operating regions.`);
+  // Only check locale if it's provided since it's an optional field
+  if (poolOptions.locale) {
+    const isLocaleInOperatingRegions = scopeOptions.ipamOperatingRegions
+      ? scopeOptions.ipamOperatingRegions.map(region => ({ regionName: region }))
+        .some(region => region.regionName === poolOptions.locale)
+      : false;
+
+    if (!isLocaleInOperatingRegions) {
+      throw new Error(`The provided locale '${poolOptions.locale}' is not in the operating regions (${scopeOptions.ipamOperatingRegions}). ` +
+        'If specified, locale must be configured as an operating region for the IPAM.');
+    }
   }
 
   return new IpamPool(scope, id, {
@@ -592,4 +596,3 @@ function createIpamPool(
     awsService: poolOptions.awsService,
   });
 }
-
diff --git a/packages/@aws-cdk/aws-ec2-alpha/test/ipam.test.ts b/packages/@aws-cdk/aws-ec2-alpha/test/ipam.test.ts
index 79a945aba0734..46d5f27ebdbc3 100644
--- a/packages/@aws-cdk/aws-ec2-alpha/test/ipam.test.ts
+++ b/packages/@aws-cdk/aws-ec2-alpha/test/ipam.test.ts
@@ -237,7 +237,11 @@ describe('IPAM Test', () => {
       publicIpSource: IpamPoolPublicIpSource.AMAZON,
       locale: 'us-west-1', // Incorrect Region
     };
-    expect(() => ipamRegion.publicScope.addPool('TestPool', poolOptions)).toThrow("The provided locale 'us-west-1' is not in the operating regions.");
+    expect(() => ipamRegion.publicScope.addPool('TestPool', poolOptions))
+      .toThrow(
+        `The provided locale 'us-west-1' is not in the operating regions (${ipamRegion.operatingRegions}). ` +
+        'If specified, locale must be configured as an operating region for the IPAM.',
+      );
   });
 
   test('IPAM handles operating regions correctly', () => {