diff --git a/.github/workflows/playwright.yml b/.github/workflows/playwright.yml
index 00cd53b..24ee373 100644
--- a/.github/workflows/playwright.yml
+++ b/.github/workflows/playwright.yml
@@ -111,6 +111,22 @@ jobs:
         env:
           BOX_API_KEY: ${{ secrets.BOX_API_KEY }}
         run: test -n "$BOX_API_KEY"
+      - name: Pick E2E ports for this runner
+        # Several runners share one host. Each runner gets its own port set so the
+        # port-freeing steps and the harness never touch another job's servers.
+        run: |
+          set -euo pipefail
+          suffix="${RUNNER_NAME##*-}"
+          offset=0
+          if [[ "$suffix" =~ ^[0-9]+$ ]]; then
+            offset=$((suffix * 100))
+          fi
+          {
+            echo "API_PORT=$((3110 + offset))"
+            echo "WEB_PORT=$((5180 + offset))"
+            echo "WWW_PORT=$((4321 + offset))"
+          } >> "$GITHUB_ENV"
+          echo "E2E ports for ${RUNNER_NAME}: api $((3110 + offset)), web $((5180 + offset)), www $((4321 + offset))"
       - name: Free stale E2E ports
         run: bash scripts/free-e2e-ports.sh
       - name: Run Playwright tests
diff --git a/scripts/free-e2e-ports.sh b/scripts/free-e2e-ports.sh
index 754bcf8..32c29d8 100755
--- a/scripts/free-e2e-ports.sh
+++ b/scripts/free-e2e-ports.sh
@@ -1,11 +1,22 @@
 #!/usr/bin/env bash
 # Free stale listeners on dedicated Playwright/E2E ports before harness bind.
 # Never touches live dev stack ports 3100 (API) or 5173 (web).
+# The ports follow API_PORT, WEB_PORT and WWW_PORT so that runners sharing one host,
+# each with its own port set, never kill another job's servers.
 
 set -euo pipefail
 
+for setting in API_PORT WEB_PORT WWW_PORT; do
+  value="${!setting:-}"
+  if [[ -n "$value" && ! "$value" =~ ^[0-9]+$ ]]; then
+    echo "free-e2e-ports: $setting must be a port number, got: $value" >&2
+    exit 1
+  fi
+done
+
 readonly LIVE_PORTS=(3100 5173)
-readonly E2E_PORTS=(3110 3111 5180 4321)
+api_port="${API_PORT:-3110}"
+readonly E2E_PORTS=("$api_port" "$((api_port + 1))" "${WEB_PORT:-5180}" "${WWW_PORT:-4321}")
 
 if [[ "$(uname -s)" != "Linux" ]]; then
   echo "free-e2e-ports: skip (not Linux)"