diff --git a/changelog.d/15268.feature b/changelog.d/15268.feature
new file mode 100644
index 000000000000..5f1f1a0f589c
--- /dev/null
+++ b/changelog.d/15268.feature
@@ -0,0 +1 @@
+Allow loading `/register/available` endpoint on workers.
diff --git a/docker/configure_workers_and_start.py b/docker/configure_workers_and_start.py
index cfb16c2e2240..291f963fd219 100755
--- a/docker/configure_workers_and_start.py
+++ b/docker/configure_workers_and_start.py
@@ -163,6 +163,7 @@
             "^/_matrix/client/versions$",
             "^/_matrix/client/(api/v1|r0|v3|unstable)/voip/turnServer$",
             "^/_matrix/client/(r0|v3|unstable)/register$",
+            "^/_matrix/client/(r0|v3|unstable)/register/available$",
             "^/_matrix/client/(r0|v3|unstable)/auth/.*/fallback/web$",
             "^/_matrix/client/(api/v1|r0|v3|unstable)/rooms/.*/messages$",
             "^/_matrix/client/(api/v1|r0|v3|unstable)/rooms/.*/event",
diff --git a/docs/workers.md b/docs/workers.md
index e0e99b44539e..bf7690f5aff2 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -245,6 +245,7 @@ information.
     # Registration/login requests
     ^/_matrix/client/(api/v1|r0|v3|unstable)/login$
     ^/_matrix/client/(r0|v3|unstable)/register$
+    ^/_matrix/client/(r0|v3|unstable)/register/available$
     ^/_matrix/client/v1/register/m.login.registration_token/validity$
 
     # Event sending requests
diff --git a/synapse/rest/client/register.py b/synapse/rest/client/register.py
index bce806f2bbb4..4adb5271d22f 100644
--- a/synapse/rest/client/register.py
+++ b/synapse/rest/client/register.py
@@ -956,7 +956,7 @@ def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     if hs.config.worker.worker_app is None:
         EmailRegisterRequestTokenRestServlet(hs).register(http_server)
         MsisdnRegisterRequestTokenRestServlet(hs).register(http_server)
-        UsernameAvailabilityRestServlet(hs).register(http_server)
         RegistrationSubmitTokenServlet(hs).register(http_server)
+    UsernameAvailabilityRestServlet(hs).register(http_server)
     RegistrationTokenValidityRestServlet(hs).register(http_server)
     RegisterRestServlet(hs).register(http_server)