diff --git a/tests/test_peer/peer.py b/tests/test_peer/peer.py
index cef2a5a..6ab0f68 100644
--- a/tests/test_peer/peer.py
+++ b/tests/test_peer/peer.py
@@ -31,6 +31,7 @@ def __init__(
         full_duplex=False,
         reply_path=None,
         locked_path=False,
+        paclen=128,
     ):
         super(TestingAX25Peer, self).__init__(
             station,
@@ -54,4 +55,5 @@ def __init__(
             full_duplex,
             reply_path,
             locked_path,
+            paclen,
         )
diff --git a/tests/test_peer/test_send.py b/tests/test_peer/test_send.py
new file mode 100644
index 0000000..fed475a
--- /dev/null
+++ b/tests/test_peer/test_send.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+
+"""
+Tests for AX25Peer transmit segmentation
+"""
+
+from aioax25.frame import (
+    AX25Address,
+)
+from .peer import TestingAX25Peer
+from ..mocks import DummyStation
+
+
+# UA reception
+
+
+def test_peer_send_short():
+    """
+    Test send accepts short payloads and enqueues a single transmission.
+    """
+    station = DummyStation(AX25Address("VK4MSL", ssid=1))
+    peer = TestingAX25Peer(
+        station=station,
+        address=AX25Address("VK4MSL"),
+        repeaters=[],
+        full_duplex=True,
+    )
+
+    peer._send_next_iframe_scheduled = False
+
+    def _send_next_iframe():
+        peer._send_next_iframe_scheduled = True
+
+    peer._send_next_iframe = _send_next_iframe
+
+    peer.send(b"Testing 1 2 3 4")
+
+    assert peer._send_next_iframe_scheduled is True
+    assert peer._pending_data == [(0xF0, b"Testing 1 2 3 4")]
+
+
+def test_peer_send_long():
+    """
+    Test send accepts long payloads and enqueues multiple transmissions.
+    """
+    station = DummyStation(AX25Address("VK4MSL", ssid=1))
+    peer = TestingAX25Peer(
+        station=station,
+        address=AX25Address("VK4MSL"),
+        repeaters=[],
+        full_duplex=True,
+    )
+
+    peer._send_next_iframe_scheduled = False
+
+    def _send_next_iframe():
+        peer._send_next_iframe_scheduled = True
+
+    peer._send_next_iframe = _send_next_iframe
+
+    peer.send(
+        b"(0) Testing 1 2 3 4 5\n(1) Testing 1 2 3 4 5\n(2) Testing 1 2 3 4 5"
+        b"\n(3) Testing 1 2 3 4 5\n(4) Testing 1 2 3 4 5\n(5) Testing 1 2 3 4"
+        b" 5\n(6) Testing 1 2 3 4 5\n(7) Testing 1 2 3 4 5\n"
+    )
+
+    assert peer._send_next_iframe_scheduled is True
+    assert peer._pending_data == [
+        (
+            0xF0,
+            b"(0) Testing 1 2 3 4 5\n(1) Testing 1 2 3 4 5\n(2) Testing "
+            b"1 2 3 4 5\n(3) Testing 1 2 3 4 5\n(4) Testing 1 2 3 4 5\n(5) "
+            b"Testing 1 2 3 ",
+        ),
+        (0xF0, b"4 5\n(6) Testing 1 2 3 4 5\n(7) Testing 1 2 3 4 5\n"),
+    ]
+
+
+def test_peer_send_paclen():
+    """
+    Test send respects PACLEN.
+    """
+    station = DummyStation(AX25Address("VK4MSL", ssid=1))
+    peer = TestingAX25Peer(
+        station=station,
+        address=AX25Address("VK4MSL"),
+        repeaters=[],
+        full_duplex=True,
+        paclen=16,
+    )
+
+    peer._send_next_iframe_scheduled = False
+
+    def _send_next_iframe():
+        peer._send_next_iframe_scheduled = True
+
+    peer._send_next_iframe = _send_next_iframe
+
+    peer.send(
+        b"(0) Testing 1 2 3 4 5\n(1) Testing 1 2 3 4 5\n(2) Testing 1 2 3 4 5"
+        b"\n(3) Testing 1 2 3 4 5\n(4) Testing 1 2 3 4 5\n(5) Testing 1 2 3 4"
+        b" 5\n(6) Testing 1 2 3 4 5\n(7) Testing 1 2 3 4 5\n"
+    )
+
+    assert peer._send_next_iframe_scheduled is True
+    assert peer._pending_data == [
+        (0xF0, b"(0) Testing 1 2 "),
+        (0xF0, b"3 4 5\n(1) Testin"),
+        (0xF0, b"g 1 2 3 4 5\n(2) "),
+        (0xF0, b"Testing 1 2 3 4 "),
+        (0xF0, b"5\n(3) Testing 1 "),
+        (0xF0, b"2 3 4 5\n(4) Test"),
+        (0xF0, b"ing 1 2 3 4 5\n(5"),
+        (0xF0, b") Testing 1 2 3 "),
+        (0xF0, b"4 5\n(6) Testing "),
+        (0xF0, b"1 2 3 4 5\n(7) Te"),
+        (0xF0, b"sting 1 2 3 4 5\n"),
+    ]