diff --git a/lib/Transport.js b/lib/Transport.js
index 8d23aea86..f25e9f82d 100644
--- a/lib/Transport.js
+++ b/lib/Transport.js
@@ -182,10 +182,14 @@ class Transport {
     let request = { abort: noop };
     const transportReturn = {
       then(onFulfilled, onRejected) {
-        return p.then(onFulfilled, onRejected);
+        if (p != null) {
+          return p.then(onFulfilled, onRejected);
+        }
       },
       catch(onRejected) {
-        return p.catch(onRejected);
+        if (p != null) {
+          return p.catch(onRejected);
+        }
       },
       abort() {
         meta.aborted = true;
@@ -194,7 +198,9 @@ class Transport {
         return this;
       },
       finally(onFinally) {
-        return p.finally(onFinally);
+        if (p != null) {
+          return p.finally(onFinally);
+        }
       },
     };
 
diff --git a/test/unit/client.test.js b/test/unit/client.test.js
index 4a4f2bf98..ce79d91c8 100644
--- a/test/unit/client.test.js
+++ b/test/unit/client.test.js
@@ -34,8 +34,9 @@ const { test } = require('tap');
 const { URL } = require('url');
 const buffer = require('buffer');
 const intoStream = require('into-stream');
-const { ConnectionPool, Transport, Connection, errors } = require('../../index');
-const { Client, buildServer } = require('../utils');
+const { ConnectionPool, Transport, Connection, errors, Client: ProductClient } = require('../../index');
+const { Client, buildServer, connection } = require('../utils');
+const { buildMockConnection } = connection
 let clientVersion = require('../../package.json').version;
 if (clientVersion.includes('-')) {
   clientVersion = clientVersion.slice(0, clientVersion.indexOf('-')) + 'p';
@@ -1189,3 +1190,130 @@ test('API compatibility header (x-ndjson)', (t) => {
     });
   });
 });
+
+test('Issue #253 with promises', async t => {
+  t.plan(1)
+
+  const delay = () => new Promise(resolve => setTimeout(resolve, 10))
+
+  const MockConnection = buildMockConnection({
+    onRequest (params) {
+      return {
+        statusCode: 200,
+        headers: {
+          'x-elastic-product': 'Elasticsearch'
+        },
+        body: {
+          name: '1ef419078577',
+          cluster_name: 'docker-cluster',
+          cluster_uuid: 'cQ5pAMvRRTyEzObH4L5mTA',
+          version: {
+            number: '8.0.0-SNAPSHOT',
+            build_flavor: 'default',
+            build_type: 'docker',
+            build_hash: '5fb4c050958a6b0b6a70a6fb3e616d0e390eaac3',
+            build_date: '2021-07-10T01:45:02.136546168Z',
+            build_snapshot: true,
+            lucene_version: '8.9.0',
+            minimum_wire_compatibility_version: '7.15.0',
+            minimum_index_compatibility_version: '7.0.0'
+          },
+          tagline: 'You Know, for Search'
+        }
+      }
+    }
+  })
+
+  class MyTransport extends Transport {
+    request (params, options = {}, callback) {
+      if (typeof options === 'function') {
+        callback = options
+        options = {}
+      }
+
+      if (typeof callback === 'undefined') {
+        return delay()
+          .then(() => super.request(params, options))
+      }
+
+      // Callback support
+      delay()
+        .then(() => super.request(params, options, callback))
+    }
+  }
+
+  const client = new ProductClient({
+    node: 'http://localhost:9200',
+    Transport: MyTransport,
+    Connection: MockConnection
+  })
+
+  try {
+    await client.search({})
+    t.pass('ok')
+  } catch (err) {
+    t.fail(err)
+  }
+})
+
+test('Issue #253 with callbacks', t => {
+  t.plan(1)
+
+  const delay = () => new Promise(resolve => setTimeout(resolve, 10))
+
+  const MockConnection = buildMockConnection({
+    onRequest (params) {
+      return {
+        statusCode: 200,
+        headers: {
+          'x-elastic-product': 'Elasticsearch'
+        },
+        body: {
+          name: '1ef419078577',
+          cluster_name: 'docker-cluster',
+          cluster_uuid: 'cQ5pAMvRRTyEzObH4L5mTA',
+          version: {
+            number: '8.0.0-SNAPSHOT',
+            build_flavor: 'default',
+            build_type: 'docker',
+            build_hash: '5fb4c050958a6b0b6a70a6fb3e616d0e390eaac3',
+            build_date: '2021-07-10T01:45:02.136546168Z',
+            build_snapshot: true,
+            lucene_version: '8.9.0',
+            minimum_wire_compatibility_version: '7.15.0',
+            minimum_index_compatibility_version: '7.0.0'
+          },
+          tagline: 'You Know, for Search'
+        }
+      }
+    }
+  })
+
+  class MyTransport extends Transport {
+    request (params, options = {}, callback) {
+      if (typeof options === 'function') {
+        callback = options
+        options = {}
+      }
+
+      if (typeof callback === 'undefined') {
+        return delay()
+          .then(() => super.request(params, options))
+      }
+
+      // Callback support
+      delay()
+        .then(() => super.request(params, options, callback))
+    }
+  }
+
+  const client = new ProductClient({
+    node: 'http://localhost:9200',
+    Transport: MyTransport,
+    Connection: MockConnection
+  })
+
+  client.search({}, (err, result) => {
+    t.error(err)
+  })
+})