diff --git a/.github/workflows/mobile-ios-release.yml b/.github/workflows/mobile-ios-release.yml
index 0fcba7b8d..b38a79b92 100644
--- a/.github/workflows/mobile-ios-release.yml
+++ b/.github/workflows/mobile-ios-release.yml
@@ -10,7 +10,7 @@ on:
   workflow_dispatch:
     inputs:
       bump_patch_version:
-        description: 'Bump the iOS marketing version patch number before release'
+        description: 'Bump the iOS marketing version patch number before release. Tick this after a version has shipped to the App Store (the release fails fast if the current version''s train is already closed).'
         required: false
         default: false
         type: boolean
diff --git a/mobile/fastlane/Fastfile b/mobile/fastlane/Fastfile
index 9053113d5..a8ccf9b8c 100644
--- a/mobile/fastlane/Fastfile
+++ b/mobile/fastlane/Fastfile
@@ -30,6 +30,20 @@ BUNDLE_ID = "com.stably.orca.mobile"
 TESTFLIGHT_GROUPS = ["peeps"].freeze
 DEFAULT_TESTFLIGHT_CHANGELOG = "Latest Orca Mobile updates and fixes.".freeze
 
+# App Store version states in which the version "train" is terminally closed to
+# new TestFlight build uploads (altool rejects with 90186 "train ... is
+# closed"). Only approved/released/removed states qualify: a version that is
+# merely IN_REVIEW / WAITING_FOR_REVIEW / PROCESSING_FOR_APP_STORE still accepts
+# TestFlight builds, so bumping on those would break normal beta iteration.
+CLOSED_APP_STORE_STATES = %w[
+  READY_FOR_SALE
+  PENDING_DEVELOPER_RELEASE
+  PENDING_APPLE_RELEASE
+  REPLACED_WITH_NEW_VERSION
+  REMOVED_FROM_SALE
+  DEVELOPER_REMOVED_FROM_SALE
+].freeze
+
 def app_store_connect_api_key_from_env
   app_store_connect_api_key(
     key_id: ENV.fetch("ASC_KEY_ID"),
@@ -71,6 +85,24 @@ def resolve_requested_version(options, config)
   truthy_option?(options[:bump_patch]) ? bump_patch_version(current_version) : current_version
 end
 
+# Returns true when `version`'s App Store train is closed to new build uploads.
+# `app` is a Spaceship::ConnectAPI::App the caller looks up (nil if lookup
+# failed). On a nil app or any API error, degrade to "open": we then proceed as
+# before this check existed — the upload either succeeds or fails with the same
+# 90186 we have always seen, never worse than today's behavior.
+def version_train_closed?(app, version)
+  return false unless app
+
+  app
+    .get_app_store_versions(filter: { versionString: version })
+    .any? { |app_store_version| CLOSED_APP_STORE_STATES.include?(app_store_version.app_store_state) }
+rescue StandardError => error
+  # Loud, not silent: a swallowed error here un-fixes the 90186 guard, so the
+  # degraded run must be visible rather than buried.
+  UI.error("Could not determine App Store state for #{version} (#{error.message}); assuming open and proceeding.")
+  false
+end
+
 def testflight_changelog
   changelog = ENV.fetch("TESTFLIGHT_CHANGELOG", "").strip
   changelog.empty? ? DEFAULT_TESTFLIGHT_CHANGELOG : changelog
@@ -83,6 +115,26 @@ platform :ios do
     config = load_mobile_app_config
     version = resolve_requested_version(options, config)
 
+    # Fail fast (seconds) if the resolved version's App Store train is already
+    # closed: Apple would otherwise reject the upload ~20 min later with 90186.
+    # Bumping the version is left to the human (the bump_patch input or a
+    # "Prepare mobile X" commit) so the marketing version stays a deliberate,
+    # release-notes-bearing decision rather than something CI invents.
+    app =
+      begin
+        Spaceship::ConnectAPI::App.find(BUNDLE_ID)
+      rescue StandardError => error
+        UI.error("Could not look up App Store app #{BUNDLE_ID} (#{error.message}); skipping closed-train check.")
+        nil
+      end
+    if version_train_closed?(app, version)
+      UI.user_error!(
+        "iOS version #{version} is already submitted/released on the App Store and cannot accept " \
+        "new builds. Re-dispatch with bump_patch_version: true (or a higher release_version), " \
+        "or land a \"Prepare mobile <version>\" commit.",
+      )
+    end
+
     latest_build_number = latest_testflight_build_number(
       api_key: api_key,
       app_identifier: BUNDLE_ID,