diff --git a/elasticapm/instrumentation/packages/httpx/async/httpcore.py b/elasticapm/instrumentation/packages/httpx/async/httpcore.py
index 061f2d87e..c7e39dbee 100644
--- a/elasticapm/instrumentation/packages/httpx/async/httpcore.py
+++ b/elasticapm/instrumentation/packages/httpx/async/httpcore.py
@@ -57,12 +57,12 @@ async def call(self, module, method, wrapped, instance, args, kwargs):
         url, method, headers = utils.get_request_data(args, kwargs)
         scheme, host, port, target = url
 
-        if port != default_ports.get(scheme):
+        if port is not None and port != default_ports.get(scheme):
             host += ":" + str(port)
 
         signature = "%s %s" % (method.upper(), host)
 
-        url = "%s://%s%s" % (scheme, host, url)
+        url = "%s://%s%s" % (scheme, host, target)
 
         transaction = execution_context.get_transaction()
 
diff --git a/elasticapm/instrumentation/packages/httpx/sync/httpcore.py b/elasticapm/instrumentation/packages/httpx/sync/httpcore.py
index 6530f703e..d03ebef2d 100644
--- a/elasticapm/instrumentation/packages/httpx/sync/httpcore.py
+++ b/elasticapm/instrumentation/packages/httpx/sync/httpcore.py
@@ -47,7 +47,7 @@ class HTTPCoreInstrumentation(AbstractInstrumentedModule):
     def call(self, module, method, wrapped, instance, args, kwargs):
         url, method, headers = utils.get_request_data(args, kwargs)
         scheme, host, port, target = url
-        if port != default_ports.get(scheme):
+        if port is not None and port != default_ports.get(scheme):
             host += ":" + str(port)
 
         signature = "%s %s" % (method.upper(), host)
diff --git a/tests/instrumentation/asyncio_tests/httpx_tests.py b/tests/instrumentation/asyncio_tests/httpx_tests.py
index 2ab017c71..01f05e938 100644
--- a/tests/instrumentation/asyncio_tests/httpx_tests.py
+++ b/tests/instrumentation/asyncio_tests/httpx_tests.py
@@ -31,6 +31,8 @@
 import pytest  # isort:skip
 
 httpx = pytest.importorskip("httpx")  # isort:skip
+httpcore = pytest.importorskip("httpcore")  # isort:skip
+
 import urllib.parse
 
 from elasticapm.conf import constants
@@ -40,6 +42,7 @@
 
 pytestmark = [pytest.mark.httpx, pytest.mark.asyncio]
 
+httpcore_version = tuple(map(int, httpcore.__version__.split(".")[:3]))
 httpx_version = tuple(map(int, httpx.__version__.split(".")[:3]))
 
 if httpx_version < (0, 20):
@@ -194,3 +197,28 @@ async def test_httpx_streaming(instrument, elasticapm_client, waiting_httpserver
     span = elasticapm_client.spans_for_transaction(transactions[0])[0]
     assert span["type"] == "external"
     assert span["subtype"] == "http"
+
+
+@pytest.mark.skipif(httpcore_version < (0, 17, 3), reason="AsyncMockBackend not available on older versions")
+async def test_default_port_handling(instrument, elasticapm_client):
+    url = "https://example.com/"
+
+    elasticapm_client.begin_transaction("transaction")
+    network_backend = httpcore.AsyncMockBackend(
+        buffer=[
+            b"HTTP/1.1 200 OK\r\n",
+            b"Content-Type: plain/text\r\n",
+            b"Content-Length: 13\r\n",
+            b"\r\n",
+            b"Hello, world!",
+        ]
+    )
+    async with httpcore.AsyncConnectionPool(network_backend=network_backend) as pool:
+        await pool.request("GET", url)
+    elasticapm_client.end_transaction("transaction")
+
+    transactions = elasticapm_client.events[TRANSACTION]
+    span = elasticapm_client.spans_for_transaction(transactions[0])[0]
+
+    assert span["name"] == "GET example.com"
+    assert span["context"]["http"]["url"] == url
diff --git a/tests/instrumentation/httpx_tests.py b/tests/instrumentation/httpx_tests.py
index 3c1b8bf15..283ee2e44 100644
--- a/tests/instrumentation/httpx_tests.py
+++ b/tests/instrumentation/httpx_tests.py
@@ -31,6 +31,8 @@
 import pytest  # isort:skip
 
 httpx = pytest.importorskip("httpx")  # isort:skip
+httpcore = pytest.importorskip("httpcore")  # isort:skip
+
 import urllib.parse
 
 from elasticapm.conf import constants
@@ -40,6 +42,7 @@
 
 pytestmark = pytest.mark.httpx
 
+httpcore_version = tuple(map(int, httpcore.__version__.split(".")[:3]))
 httpx_version = tuple(map(int, httpx.__version__.split(".")[:3]))
 
 if httpx_version < (0, 20):
@@ -136,6 +139,29 @@ def test_httpx_instrumentation_malformed_path(instrument, elasticapm_client):
             httpx.get("http://")
 
 
+@pytest.mark.skipif(httpcore_version < (0, 17, 3), reason="MockBackend not available on older versions")
+def test_default_port_handling(instrument, elasticapm_client):
+    url = "https://example.com/"
+    elasticapm_client.begin_transaction("transaction")
+    network_backend = httpcore.MockBackend(
+        buffer=[
+            b"HTTP/1.1 200 OK\r\n",
+            b"Content-Type: plain/text\r\n",
+            b"Content-Length: 13\r\n",
+            b"\r\n",
+            b"Hello, world!",
+        ]
+    )
+    with httpcore.ConnectionPool(network_backend=network_backend) as pool:
+        pool.request("GET", url)
+    elasticapm_client.end_transaction("transaction")
+    transactions = elasticapm_client.events[TRANSACTION]
+    span = elasticapm_client.spans_for_transaction(transactions[0])[0]
+
+    assert span["name"] == "GET example.com"
+    assert span["context"]["http"]["url"] == url
+
+
 def test_url_sanitization(instrument, elasticapm_client, waiting_httpserver):
     waiting_httpserver.serve_content("")
     url = waiting_httpserver.url + "/hello_world"