diff --git a/utils/e2e-tests/bash/tests/base/block-check.sh b/utils/e2e-tests/bash/tests/base/block-check.sh
index e37ee17a1..683bbadd2 100755
--- a/utils/e2e-tests/bash/tests/base/block-check.sh
+++ b/utils/e2e-tests/bash/tests/base/block-check.sh
@@ -5,6 +5,9 @@ get_address() {
   "$HUMANODE_PEER_PATH" key inspect "$@" | grep "SS58 Address:" | awk '{print $3}'
 }
 
+RPC_URL_HTTP="http://127.0.0.1:9944"
+RPC_URL_WS="ws://127.0.0.1:9944"
+
 # Make temporary test directory.
 TEMPDIR="$(mktemp -d)"
 trap 'rm -rf "$TEMPDIR"; pkill -P "$$"' EXIT
@@ -15,9 +18,40 @@ trap 'rm -rf "$TEMPDIR"; pkill -P "$$"' EXIT
 # Get the address.
 ADDR="$(get_address "//Alice")"
 
+# Wait for the RPC endpoint to come up before submitting anything, so that the
+# client does not race the node startup. Fail explicitly if it never does.
+RPC_WAIT_TIMEOUT_SEC=30
+RPC_WAIT_ANCHOR="$SECONDS"
+until curl \
+  --silent \
+  --output /dev/null \
+  --header 'Content-Type: application/json' \
+  --data '{"jsonrpc":"2.0","id":1,"method":"system_health","params":[]}' \
+  "$RPC_URL_HTTP"; do
+  if (("$SECONDS" - "$RPC_WAIT_ANCHOR" >= RPC_WAIT_TIMEOUT_SEC)); then
+    printf "RPC endpoint did not come up within %d seconds\n" "$RPC_WAIT_TIMEOUT_SEC" >&2
+    exit 1
+  fi
+  sleep 0.2
+done
+printf "RPC endpoint is up after %d seconds\n" "$(("$SECONDS" - "$RPC_WAIT_ANCHOR"))" >&2
+
 # Send TX and wait for block creation.
-# The test will also fail if no block is created within 20 sec.
-POLKA_JSON="$(timeout 30 yarn workspace humanode-e2e-tests-bash polkadot-js-api --ws "ws://127.0.0.1:9944" --seed "//Alice" tx.balances.transfer "$ADDR" 10000)"
+# The test will also fail if no block is created within 30 sec.
+#
+# The client output is streamed to stderr as it arrives (in addition to being
+# captured), so that it is visible in the logs even if the command times out.
+# DEBUG=api-ws makes the polkadot-js WebSocket provider log every request,
+# response and connection event to stderr; DEBUG_MAX truncates each logged
+# value (the metadata response alone is hundreds of KB otherwise).
+POLKA_JSON="$(
+  DEBUG=api-ws DEBUG_MAX=1000 timeout 30 \
+    yarn workspace humanode-e2e-tests-bash polkadot-js-api \
+    --ws "$RPC_URL_WS" \
+    --seed "//Alice" \
+    tx.balances.transfer "$ADDR" 10000 |
+    tee /dev/stderr
+)"
 
 # Log polkadot-js-api response.
 printf "polkadot-js-api response:\n%s\n" "$POLKA_JSON" >&2