diff --git a/src/__tests__/utils/request-router.test.ts b/src/__tests__/utils/request-router.test.ts
index d8a87e74c..9075669d9 100644
--- a/src/__tests__/utils/request-router.test.ts
+++ b/src/__tests__/utils/request-router.test.ts
@@ -12,7 +12,7 @@ describe('request-router', () => {
 
     const testCases: [string, RequestRouterTarget, string][] = [
         // US domain
-        ['https://app.posthog.com', 'ui', 'https://app.posthog.com'],
+        ['https://app.posthog.com', 'ui', 'https://us.posthog.com'],
         ['https://app.posthog.com', 'assets', 'https://us-assets.i.posthog.com'],
         ['https://app.posthog.com', 'api', 'https://us.i.posthog.com'],
         // US domain via app domain
@@ -26,6 +26,7 @@ describe('request-router', () => {
 
         // EU domain
         ['https://eu.posthog.com', 'ui', 'https://eu.posthog.com'],
+        ['https://eu.i.posthog.com', 'ui', 'https://eu.posthog.com'],
         ['https://eu.posthog.com', 'assets', 'https://eu-assets.i.posthog.com'],
         ['https://eu.posthog.com', 'api', 'https://eu.i.posthog.com'],
         ['https://eu.i.posthog.com', 'api', 'https://eu.i.posthog.com'],
diff --git a/src/utils/request-router.ts b/src/utils/request-router.ts
index 9f484cbc8..da635f78b 100644
--- a/src/utils/request-router.ts
+++ b/src/utils/request-router.ts
@@ -27,14 +27,25 @@ export class RequestRouter {
     }
 
     get apiHost(): string {
-        return this.instance.config.api_host.trim().replace(/\/$/, '')
+        const host = this.instance.config.api_host.trim().replace(/\/$/, '')
+        if (host === 'https://app.posthog.com') {
+            return 'https://us.i.posthog.com'
+        }
+        return host
     }
     get uiHost(): string | undefined {
-        const host = this.instance.config.ui_host?.replace(/\/$/, '')
+        let host = this.instance.config.ui_host?.replace(/\/$/, '')
+
+        if (!host) {
+            // No ui_host set, get it from the api_host. But api_host differs
+            // from the actual UI host, so replace the ingestion subdomain with just posthog.com
+            host = this.apiHost.replace(`.${ingestionDomain}`, '.posthog.com')
+        }
 
         if (host === 'https://app.posthog.com') {
             return 'https://us.posthog.com'
         }
+
         return host
     }
 
@@ -58,7 +69,7 @@ export class RequestRouter {
         }
 
         if (target === 'ui') {
-            return (this.uiHost || this.apiHost.replace(`.${ingestionDomain}`, '.posthog.com')) + path
+            return this.uiHost + path
         }
 
         if (this.region === RequestRouterRegion.CUSTOM) {