diff --git a/pyproject.toml b/pyproject.toml
index e64149db..2d1414af 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -81,7 +81,7 @@ dev = [
 
 a2a = [
   # go/keep-sorted start
-  "a2a-sdk>=0.2.16,<0.3.0;python_version>='3.10'",
+  "a2a-sdk>=0.3.0,<0.4.0;python_version>='3.10'",
   # go/keep-sorted end
 ]
 
diff --git a/src/google/adk/a2a/logs/log_utils.py b/src/google/adk/a2a/logs/log_utils.py
index 901cd631..78ca4371 100644
--- a/src/google/adk/a2a/logs/log_utils.py
+++ b/src/google/adk/a2a/logs/log_utils.py
@@ -136,11 +136,11 @@ def build_a2a_request_log(req: SendMessageRequest) -> str:
   config_log = "None"
   if req.params.configuration:
     config_data = {
-        "acceptedOutputModes": req.params.configuration.acceptedOutputModes,
+        "accepted_output_modes": req.params.configuration.accepted_output_modes,
         "blocking": req.params.configuration.blocking,
-        "historyLength": req.params.configuration.historyLength,
-        "pushNotificationConfig": bool(
-            req.params.configuration.pushNotificationConfig
+        "history_length": req.params.configuration.history_length,
+        "push_notification_config": bool(
+            req.params.configuration.push_notification_config
         ),
     }
     config_log = json.dumps(config_data, indent=2)
diff --git a/src/google/adk/agents/remote_a2a_agent.py b/src/google/adk/agents/remote_a2a_agent.py
index 02d06a1b..cc9fb75a 100644
--- a/src/google/adk/agents/remote_a2a_agent.py
+++ b/src/google/adk/agents/remote_a2a_agent.py
@@ -26,7 +26,7 @@ import uuid
 
 try:
   from a2a.client import A2AClient
-  from a2a.client.client import A2ACardResolver
+  from a2a.client.card_resolver import A2ACardResolver
   from a2a.types import AgentCard
   from a2a.types import Message as A2AMessage
   from a2a.types import MessageSendParams as A2AMessageSendParams
diff --git a/tests/unittests/a2a/logs/test_log_utils.py b/tests/unittests/a2a/logs/test_log_utils.py
index 2ca432cc..9673dab4 100644
--- a/tests/unittests/a2a/logs/test_log_utils.py
+++ b/tests/unittests/a2a/logs/test_log_utils.py
@@ -184,7 +184,7 @@ class TestBuildA2ARequestLog:
     assert "Part 0:" in result
     assert "Part 1:" in result
     assert '"blocking": true' in result
-    assert '"historyLength": 10' in result
+    assert '"history_length": 10' in result
     assert '"key1": "value1"' in result
 
   def test_request_without_parts(self):
diff --git a/tests/unittests/agents/test_remote_a2a_agent.py b/tests/unittests/agents/test_remote_a2a_agent.py
index fa1a20fe..7ef32de6 100644
--- a/tests/unittests/agents/test_remote_a2a_agent.py
+++ b/tests/unittests/agents/test_remote_a2a_agent.py
@@ -20,7 +20,10 @@ from unittest.mock import AsyncMock
 from unittest.mock import Mock
 from unittest.mock import patch
 
-# Try to import a2a library - will fail on Python < 3.10
+import pytest
+
+# Check if A2A dependencies are available
+A2A_AVAILABLE = True
 try:
   from a2a.types import AgentCapabilities
   from a2a.types import AgentCard
@@ -32,32 +35,34 @@ try:
   from google.adk.agents.remote_a2a_agent import A2A_METADATA_PREFIX
   from google.adk.agents.remote_a2a_agent import AgentCardResolutionError
   from google.adk.agents.remote_a2a_agent import RemoteA2aAgent
-
-  A2A_AVAILABLE = True
 except ImportError:
   A2A_AVAILABLE = False
+
   # Create dummy classes to prevent NameError during test collection
-  AgentCapabilities = type("AgentCapabilities", (), {})
-  AgentCard = type("AgentCard", (), {})
-  AgentSkill = type("AgentSkill", (), {})
-  A2AMessage = type("A2AMessage", (), {})
-  SendMessageSuccessResponse = type("SendMessageSuccessResponse", (), {})
-  A2ATask = type("A2ATask", (), {})
+  class DummyTypes:
+    pass
+
+  AgentCapabilities = DummyTypes()
+  AgentCard = DummyTypes()
+  AgentSkill = DummyTypes()
+  A2AMessage = DummyTypes()
+  SendMessageSuccessResponse = DummyTypes()
+  A2ATask = DummyTypes()
+  InvocationContext = DummyTypes()
+  RemoteA2aAgent = DummyTypes()
+  AgentCardResolutionError = Exception
+  A2A_METADATA_PREFIX = ""
+
+# Skip all tests in this module if Python < 3.10 or A2A dependencies are not available
+pytestmark = pytest.mark.skipif(
+    sys.version_info < (3, 10) or not A2A_AVAILABLE,
+    reason="A2A requires Python 3.10+ and A2A dependencies must be available",
+)
 
 
 from google.adk.events.event import Event
 from google.adk.sessions.session import Session
 import httpx
-import pytest
-
-# Skip all tests in this module if Python < 3.10 or a2a library is not available
-pytestmark = pytest.mark.skipif(
-    sys.version_info < (3, 10) or not A2A_AVAILABLE,
-    reason=(
-        "a2a library requires Python 3.10+ and is not available, skipping"
-        " RemoteA2aAgent tests"
-    ),
-)
 
 
 # Helper function to create a proper AgentCard for testing