diff --git a/elastic_transport/connection/base.py b/elastic_transport/connection/base.py
index 2a18830..7025ceb 100644
--- a/elastic_transport/connection/base.py
+++ b/elastic_transport/connection/base.py
@@ -51,6 +51,8 @@ class Connection(object):
     :arg user_agent: 'User-Agent' HTTP header for the given service.
     """
 
+    HTTP_CLIENT_META = None
+
     def __init__(
         self,
         host="localhost",
diff --git a/elastic_transport/connection/http_requests.py b/elastic_transport/connection/http_requests.py
index 108530b..206efb9 100644
--- a/elastic_transport/connection/http_requests.py
+++ b/elastic_transport/connection/http_requests.py
@@ -20,17 +20,19 @@
 
 import urllib3
 
+from ..compat import urlencode
+from ..exceptions import ConnectionError, ConnectionTimeout
+from ..utils import DEFAULT, client_meta_version, normalize_headers
+from .base import Connection
+
 try:
     import requests
 
-    REQUESTS_AVAILABLE = True
+    _REQUESTS_AVAILABLE = True
+    _REQUESTS_META_VERSION = client_meta_version(requests.__version__)
 except ImportError:  # pragma: nocover
-    REQUESTS_AVAILABLE = False
-
-from ..compat import urlencode
-from ..exceptions import ConnectionError, ConnectionTimeout
-from ..utils import DEFAULT, normalize_headers
-from .base import Connection
+    _REQUESTS_AVAILABLE = False
+    _REQUESTS_META_VERSION = ""
 
 
 class RequestsHttpConnection(Connection):
@@ -52,6 +54,8 @@ class RequestsHttpConnection(Connection):
         For tracing all requests made by this transport.
     """
 
+    HTTP_CLIENT_META = ("rq", _REQUESTS_META_VERSION)
+
     def __init__(
         self,
         host="localhost",
@@ -67,7 +71,7 @@ def __init__(
         opaque_id=None,
         **kwargs
     ):
-        if not REQUESTS_AVAILABLE:  # pragma: nocover
+        if not _REQUESTS_AVAILABLE:  # pragma: nocover
             raise ValueError(
                 "You must have 'requests' installed to use RequestsHttpConnection"
             )
diff --git a/elastic_transport/connection/http_urllib3.py b/elastic_transport/connection/http_urllib3.py
index 87dbb18..bd5c336 100644
--- a/elastic_transport/connection/http_urllib3.py
+++ b/elastic_transport/connection/http_urllib3.py
@@ -25,7 +25,7 @@
 
 from ..compat import urlencode
 from ..exceptions import ConnectionError, ConnectionTimeout
-from ..utils import DEFAULT, normalize_headers
+from ..utils import DEFAULT, client_meta_version, normalize_headers
 from .base import Connection
 
 CA_CERTS = None
@@ -70,6 +70,8 @@ class Urllib3HttpConnection(Connection):
         For tracing all requests made by this transport.
     """
 
+    HTTP_CLIENT_META = ("ur", client_meta_version(urllib3.__version__))
+
     def __init__(
         self,
         host="localhost",
diff --git a/elastic_transport/transport.py b/elastic_transport/transport.py
index e08bc69..fa763de 100644
--- a/elastic_transport/transport.py
+++ b/elastic_transport/transport.py
@@ -15,13 +15,16 @@
 #  specific language governing permissions and limitations
 #  under the License.
 
+from platform import python_version
+
+from ._version import __version__
 from .compat import string_types, urlparse
 from .connection import RequestsHttpConnection, Urllib3HttpConnection
 from .connection_pool import ConnectionPool, DummyConnectionPool, EmptyConnectionPool
 from .exceptions import ConnectionError, ConnectionTimeout, TransportError
 from .response import DictResponse, ListResponse, Response
 from .serializer import DEFAULT_SERIALIZERS, Deserializer
-from .utils import DEFAULT, normalize_headers
+from .utils import DEFAULT, client_meta_version, normalize_headers
 
 # Allows for using a connection_class by name rather than import.
 CONNECTION_CLASS_NAMES = {
@@ -89,6 +92,19 @@ def __init__(
                 )
             connection_class = CONNECTION_CLASS_NAMES[connection_class]
 
+        # Create the default metadata for the x-elastic-client-meta
+        # HTTP header. Only requires adding the (service, service_version)
+        # tuple to the beginning of the client_meta
+        self.transport_client_meta = (
+            ("py", client_meta_version(python_version())),
+            ("t", client_meta_version(__version__)),
+        )
+
+        # Grab the 'HTTP_CLIENT_META' property from the connection class
+        http_client_meta = getattr(connection_class, "HTTP_CLIENT_META", None)
+        if http_client_meta:
+            self.transport_client_meta += (http_client_meta,)
+
         # serialization config
         _serializers = DEFAULT_SERIALIZERS.copy()
         # if custom serializers map has been supplied, override the defaults with it
diff --git a/elastic_transport/utils.py b/elastic_transport/utils.py
index 614912c..f424d08 100644
--- a/elastic_transport/utils.py
+++ b/elastic_transport/utils.py
@@ -16,6 +16,7 @@
 #  under the License.
 
 import binascii
+import re
 from collections import namedtuple
 from platform import python_version
 
@@ -39,6 +40,16 @@ def create_user_agent(name, version):
     )
 
 
+def client_meta_version(ver):
+    """Converts a Python package version to a meta version.
+    Meta version simply adds a 'p' suffix for all pre-releases
+    """
+    ver, ver_is_pre = re.match(r"^([0-9][0-9.]*[0-9]|[0-9])(.*)$", ver).groups()
+    if ver_is_pre:
+        ver += "p"
+    return ver
+
+
 def normalize_headers(headers):
     """Normalizes HTTP headers to be lowercase to ensure
     there are no case-collisions deeper within the stack.
diff --git a/tests/test_transport.py b/tests/test_transport.py
index 7ee4d6d..4d05e17 100644
--- a/tests/test_transport.py
+++ b/tests/test_transport.py
@@ -16,6 +16,8 @@
 #  specific language governing permissions and limitations
 #  under the License.
 
+import re
+
 import mock
 import pytest
 
@@ -398,3 +400,21 @@ def test_head_response_ignore_status(status):
     assert resp == False  # noqa
     assert resp.body is False
     assert bool(resp) is False
+
+
+@pytest.mark.parametrize(
+    "connection_class",
+    ["urllib3", "requests", Urllib3HttpConnection, RequestsHttpConnection],
+)
+def test_transport_client_meta_connection_class(connection_class):
+    t = Transport(connection_class=connection_class)
+    assert t.transport_client_meta[2] == t.connection_class.HTTP_CLIENT_META
+    assert t.transport_client_meta[2][0] in ("ur", "rq")
+    assert re.match(
+        r"^py=[0-9.]+p?,t=[0-9.]+p?,(?:ur|rq)=[0-9.]+p?$",
+        ",".join("%s=%s" % (k, v) for k, v in t.transport_client_meta),
+    )
+
+    t = Transport()
+    assert t.transport_client_meta[2][0] == "ur"
+    assert [x[0] for x in t.transport_client_meta[:2]] == ["py", "t"]
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 91ca083..028f71b 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -21,7 +21,11 @@
 import pytest
 
 from elastic_transport import __version__
-from elastic_transport.utils import create_user_agent, parse_cloud_id
+from elastic_transport.utils import (
+    client_meta_version,
+    create_user_agent,
+    parse_cloud_id,
+)
 
 
 def test_create_user_agent():
@@ -33,6 +37,19 @@ def test_create_user_agent():
     )
 
 
+@pytest.mark.parametrize(
+    ["version", "meta_version"],
+    [
+        ("7.10.0", "7.10.0"),
+        ("7.10.0-alpha1", "7.10.0p"),
+        ("3.9.0b1", "3.9.0p"),
+        ("3.9.pre1", "3.9p"),
+    ],
+)
+def test_client_meta_version(version, meta_version):
+    assert client_meta_version(version) == meta_version
+
+
 def test_parse_cloud_id():
     cloud_id = parse_cloud_id(
         "cluster:dXMtZWFzdC0xLmF3cy5mb3VuZC5pbyQ0ZmE4ODIxZTc1NjM0MDMyYmVkMWNmMjIxMTBlMmY5NyQ0ZmE4ODIxZTc1NjM0MDMyYmVkMWNmMjIxMTBlMmY5Ng=="