diff --git a/tests/toranj/start.sh b/tests/toranj/start.sh
index 443fdcc75..377b2c8d5 100755
--- a/tests/toranj/start.sh
+++ b/tests/toranj/start.sh
@@ -115,6 +115,7 @@ run test-005-discover-scan.py
 run test-006-traffic-router-end-device.py
 run test-007-traffic-router-sleepy.py
 run test-008-permit-join.py
+run test-009-insecure-traffic-join.py
 run test-100-mcu-power-state.py
 
 run test-600-channel-manager-properties.py
diff --git a/tests/toranj/test-009-insecure-traffic-join.py b/tests/toranj/test-009-insecure-traffic-join.py
new file mode 100644
index 000000000..18f0f57b9
--- /dev/null
+++ b/tests/toranj/test-009-insecure-traffic-join.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+#
+#  Copyright (c) 2018, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+
+import time
+import wpan
+from wpan import verify
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Test description: Check insecure data transmission during joining.
+
+test_name = __file__[:-3] if __file__.endswith('.py') else __file__
+print '-' * 120
+print 'Starting \'{}\''.format(test_name)
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Creating `wpan.Nodes` instances
+
+node1 = wpan.Node()
+node2 = wpan.Node()
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Init all nodes
+
+wpan.Node.init_all_nodes()
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Build network topology
+
+node1.form("insec-join-test")
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Test implementation
+
+insecure_port = 1234
+NUM_MSGS = 4
+
+# Make node1 joinable and set the insecure port
+node1.permit_join(duration_sec='100', port=str(insecure_port))
+verify(node1.get(wpan.WPAN_NETWORK_ALLOW_JOIN) == 'true')
+
+# Join node1 network from node2 without setting the key
+node2.join_node(node1, should_set_key=False)
+
+verify(node2.get(wpan.WPAN_STATE) == wpan.STATE_CREDENTIALS_NEEDED)
+verify(node2.get(wpan.WPAN_NAME) == node1.get(wpan.WPAN_NAME))
+verify(node2.get(wpan.WPAN_PANID) == node1.get(wpan.WPAN_PANID))
+verify(node2.get(wpan.WPAN_XPANID) == node1.get(wpan.WPAN_XPANID))
+
+ll1 = node1.get(wpan.WPAN_IP6_LINK_LOCAL_ADDRESS)[1:-1]
+ll2 = node2.get(wpan.WPAN_IP6_LINK_LOCAL_ADDRESS)[1:-1]
+
+# Send insecure traffic from node2 to node1 using link-local IP address for src/dst and insecure port number
+
+sender = node2.prepare_tx(ll2, (ll1, insecure_port), "Hi (insecure)", NUM_MSGS)
+recver = node1.prepare_rx(sender)
+wpan.Node.perform_async_tx_rx()
+verify(sender.was_successful)
+verify(recver.was_successful)
+
+# Get the random src port number used by node1 and ensure node2 allows insecure rx traffic on that port
+
+rx_port = recver.all_rx_msg[0][1][1]
+node2.permit_join(duration_sec='100', port=str(rx_port))
+
+# Send insecure reply from node1 to node2
+
+sender2 = node1.prepare_tx((ll1, insecure_port), (ll2, rx_port), "Hi back! (insecure)", NUM_MSGS)
+recver2 = node2.prepare_rx(sender2)
+wpan.Node.perform_async_tx_rx()
+verify(sender2.was_successful)
+verify(recver2.was_successful)
+
+# Now node2 fully joins the network (set the network key), check all secure traffic exchange between the nodes
+
+node2.set(wpan.WPAN_KEY, node1.get(wpan.WPAN_KEY)[1:-1], binary_data=True)
+verify(node2.is_associated())
+
+node1.permit_join('0')
+
+sender = node2.prepare_tx(ll2, (ll1, insecure_port), "Hi (now secure)", NUM_MSGS)
+recver = node1.prepare_rx(sender)
+wpan.Node.perform_async_tx_rx()
+verify(sender.was_successful)
+verify(recver.was_successful)
+
+node2.permit_join('0')
+
+sender2 = node1.prepare_tx((ll1, insecure_port), (ll2, rx_port), "Hi back! (secure now)", NUM_MSGS)
+recver2 = node2.prepare_rx(sender2)
+wpan.Node.perform_async_tx_rx()
+verify(sender2.was_successful)
+verify(recver2.was_successful)
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Test finished
+
+print '\'{}\' passed.'.format(test_name)