diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e6f4b5ae876..a5c98965d32 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -91,7 +91,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        part: [1, 2]  # TODO: parts 3,4 blocked on chunked Transfer-Encoding revad bug — follow-up PR
+        part: [1, 2, 3, 4]  # FIXME: parts 3,4 blocked on chunked Transfer-Encoding revad bug — follow-up PR
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
@@ -107,7 +107,27 @@ jobs:
           name: acceptance-ocis-part-${{ matrix.part }}
           path: tmp/testrunner/tests/acceptance/output/
 
-  # TODO: acceptance-tests-s3ng skipped — blocked on Ceph networking — follow-up PR
+  acceptance-tests-s3ng:
+    needs: [unit-tests]
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        part: [1, 2, 3, 4, 5, 6]
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
+        with:
+          go-version-file: go.mod
+      - uses: shivammathur/setup-php@accd6127cb78bee3e8082180cb391013d204ef9f # v2
+        with:
+          php-version: "8.4"
+      - run: python3 tests/acceptance/run-acceptance.py --storage s3ng --total-parts 6 --run-part ${{ matrix.part }}
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        if: failure()
+        with:
+          name: acceptance-s3ng-part-${{ matrix.part }}
+          path: tmp/testrunner/tests/acceptance/output/
 
   acceptance-tests-posixfs:
     needs: [unit-tests]
@@ -115,7 +135,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        part: [1, 2]  # TODO: parts 3,4 blocked on chunked Transfer-Encoding revad bug — follow-up PR
+        part: [1, 2, 3, 4]  # FIXME: parts 3,4 blocked on chunked Transfer-Encoding revad bug — follow-up PR
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
@@ -142,6 +162,7 @@ jobs:
       - litmus
       - cs3api-validator
       - acceptance-tests-ocis
+      - acceptance-tests-s3ng
       - acceptance-tests-posixfs
     runs-on: ubuntu-latest
     steps:
@@ -154,6 +175,7 @@ jobs:
             "${{ needs.litmus.result }}"
             "${{ needs.cs3api-validator.result }}"
             "${{ needs.acceptance-tests-ocis.result }}"
+            "${{ needs.acceptance-tests-s3ng.result }}"
             "${{ needs.acceptance-tests-posixfs.result }}"
           )
           for r in "${results[@]}"; do
diff --git a/tests/acceptance/run-acceptance.py b/tests/acceptance/run-acceptance.py
index 40287c8650e..8b822de9d6e 100755
--- a/tests/acceptance/run-acceptance.py
+++ b/tests/acceptance/run-acceptance.py
@@ -185,6 +185,16 @@ def start_redis():
     wait_for_port(REDIS_PORT, timeout=30, label="Redis")
 
 
+def ceph_rgw_ready():
+    """Check RGW is actually responding (not just Docker proxy listening)."""
+    r = subprocess.run(
+        ["curl", "-sf", "--max-time", "2", f"http://localhost:{CEPH_PORT}"],
+        capture_output=True,
+    )
+    # RGW returns XML even for anonymous requests — any HTTP response means it's up
+    return r.returncode == 0
+
+
 def start_ceph():
     print("Starting Ceph...")
     subprocess.run(
@@ -203,9 +213,18 @@ def start_ceph():
          CEPH_IMAGE],
         check=True,
     )
-    wait_for_port(CEPH_PORT, timeout=180, label="Ceph RGW")
-    # Wait for demo bucket creation after RGW starts accepting connections
-    time.sleep(15)
+    # Docker port mapping makes TCP port appear open before RGW binds inside container.
+    # Must use HTTP check to verify RGW is actually responding.
+    start = time.time()
+    while time.time() - start < 180:
+        if ceph_rgw_ready():
+            print("Ceph RGW ready.", flush=True)
+            # Extra wait for demo bucket creation after RGW starts
+            time.sleep(10)
+            return
+        time.sleep(2)
+    subprocess.run(["docker", "logs", "--tail", "50", "ceph"])
+    sys.exit("Timeout waiting for Ceph RGW after 180s")
 
 
 SERVICE_STARTERS = {
diff --git a/tests/acceptance/run-cs3api.py b/tests/acceptance/run-cs3api.py
index 21f5a6f06ca..ca960c82f9d 100755
--- a/tests/acceptance/run-cs3api.py
+++ b/tests/acceptance/run-cs3api.py
@@ -114,6 +114,14 @@ def prepare_configs(storage):
     return config_dir
 
 
+def ceph_rgw_ready():
+    r = subprocess.run(
+        ["curl", "-sf", "--max-time", "2", f"http://localhost:{CEPH_PORT}"],
+        capture_output=True,
+    )
+    return r.returncode == 0
+
+
 def start_ceph():
     print("Starting Ceph...")
     env_args = []
@@ -126,9 +134,15 @@ def start_ceph():
         env_args + [CEPH_IMAGE],
         check=True,
     )
-    wait_for_port(CEPH_PORT, timeout=180, label="Ceph RGW")
-    # Wait for demo bucket creation after RGW starts accepting connections
-    time.sleep(15)
+    start = time.time()
+    while time.time() - start < 180:
+        if ceph_rgw_ready():
+            print("Ceph RGW ready.", flush=True)
+            time.sleep(10)
+            return
+        time.sleep(2)
+    subprocess.run(["docker", "logs", "--tail", "50", "ceph"])
+    sys.exit("Timeout waiting for Ceph RGW after 180s")
 
 
 def start_revad_services(config_dir, storage):