diff --git a/tests/sys/netpfil/pf/nat64.sh b/tests/sys/netpfil/pf/nat64.sh
index 0ae2c0399daf..9e91e95570c1 100644
--- a/tests/sys/netpfil/pf/nat64.sh
+++ b/tests/sys/netpfil/pf/nat64.sh
@@ -1,184 +1,213 @@
 #
 # SPDX-License-Identifier: BSD-2-Clause
 #
 # Copyright (c) 2024 Rubicon Communications, LLC (Netgate)
 #
 # 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.
 #
 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 
 . $(atf_get_srcdir)/utils.subr
 
 nat64_setup()
 {
 	pft_init
 
 	epair_link=$(vnet_mkepair)
 	epair=$(vnet_mkepair)
 
 	ifconfig ${epair}a inet6 2001:db8::2/64 up no_dad
 	route -6 add default 2001:db8::1
 
 	vnet_mkjail rtr ${epair}b ${epair_link}a
 	jexec rtr ifconfig ${epair}b inet6 2001:db8::1/64 up no_dad
 	jexec rtr ifconfig ${epair_link}a 192.0.2.1/24 up
 
 	vnet_mkjail dst ${epair_link}b
 	jexec dst ifconfig ${epair_link}b 192.0.2.2/24 up
 	jexec dst route add default 192.0.2.1
 
 	# Sanity checks
 	atf_check -s exit:0 -o ignore \
 	    ping6 -c 1 2001:db8::1
 	atf_check -s exit:0 -o ignore \
 	    jexec dst ping -c 1 192.0.2.1
 
 	jexec rtr pfctl -e
 	pft_set_rules rtr \
+	    "set reassemble yes" \
 	    "set state-policy if-bound" \
 	    "pass in on ${epair}b inet6 from any to 64:ff9b::/96 af-to inet from (${epair_link}a)"
 }
 
 atf_test_case "icmp_echo" "cleanup"
 icmp_echo_head()
 {
 	atf_set descr 'Basic NAT64 ICMP echo test'
 	atf_set require.user root
 }
 
 icmp_echo_body()
 {
 	nat64_setup
 
 	# One ping
 	atf_check -s exit:0 -o ignore \
 	    ping6 -c 1 64:ff9b::192.0.2.2
 
 	# Make sure packets make it even when state is established
 	atf_check -s exit:0 \
 	    -o match:'5 packets transmitted, 5 packets received, 0.0% packet loss' \
 	    ping6 -c 5 64:ff9b::192.0.2.2
 }
 
 icmp_echo_cleanup()
 {
 	pft_cleanup
 }
 
+atf_test_case "fragmentation" "cleanup"
+fragmentation_head()
+{
+	atf_set descr 'Test fragmented packets'
+	atf_set require.user root
+}
+
+fragmentation_body()
+{
+	nat64_setup
+
+	atf_check -s exit:0 -o ignore \
+	    ping6 -c 1 -s 1280 64:ff9b::192.0.2.2
+
+	atf_check -s exit:0 \
+	    -o match:'3 packets transmitted, 3 packets received, 0.0% packet loss' \
+	    ping6 -c 3 -s 2000 64:ff9b::192.0.2.2
+	atf_check -s exit:0 \
+	    -o match:'3 packets transmitted, 3 packets received, 0.0% packet loss' \
+	    ping6 -c 3 -s 10000 -b 20000 64:ff9b::192.0.2.2
+}
+
+fragmentation_cleanup()
+{
+	pft_cleanup
+}
+
 atf_test_case "tcp" "cleanup"
 tcp_head()
 {
 	atf_set descr 'TCP NAT64 test'
 	atf_set require.user root
 }
 
 tcp_body()
 {
 	nat64_setup
 
 	echo "foo" | jexec dst nc -l 1234 &
 
 	# Sanity check & delay for nc startup
 	atf_check -s exit:0 -o ignore \
 	    ping6 -c 1 64:ff9b::192.0.2.2
 
 	rcv=$(nc -w 3 -6 64:ff9b::c000:202 1234)
 	if [ "${rcv}" != "foo" ];
 	then
 		echo "rcv=${rcv}"
 		atf_fail "Failed to connect to TCP server"
 	fi
 }
 
 tcp_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "udp" "cleanup"
 udp_head()
 {
 	atf_set descr 'UDP NAT64 test'
 	atf_set require.user root
 }
 
 udp_body()
 {
 	nat64_setup
 
 	echo "foo" | jexec dst nc -u -l 1234 &
 
 	# Sanity check & delay for nc startup
 	atf_check -s exit:0 -o ignore \
 	    ping6 -c 1 64:ff9b::192.0.2.2
 
 	rcv=$(echo bar | nc -w 3 -6 -u 64:ff9b::c000:202 1234)
 	if [ "${rcv}" != "foo" ];
 	then
 		echo "rcv=${rcv}"
 		atf_fail "Failed to connect to UDP server"
 	fi
 }
 
 udp_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "sctp" "cleanup"
 sctp_head()
 {
 	atf_set descr 'SCTP NAT64 test'
 	atf_set require.user root
 }
 
 sctp_body()
 {
 	nat64_setup
 	if ! kldstat -q -m sctp; then
 		atf_skip "This test requires SCTP"
 	fi
 
 	echo "foo" | jexec dst nc --sctp -N -l 1234 &
 
 	# Sanity check & delay for nc startup
 	atf_check -s exit:0 -o ignore \
 	    ping6 -c 1 64:ff9b::192.0.2.2
 
 	rcv=$(echo bar | nc --sctp -w 3 -6 64:ff9b::c000:202 1234)
 	if [ "${rcv}" != "foo" ];
 	then
 		echo "rcv=${rcv}"
 		atf_fail "Failed to connect to SCTP server"
 	fi
 }
 
 sctp_cleanup()
 {
 	pft_cleanup
 }
 
 atf_init_test_cases()
 {
 	atf_add_test_case "icmp_echo"
+	atf_add_test_case "fragmentation"
 	atf_add_test_case "tcp"
 	atf_add_test_case "udp"
 	atf_add_test_case "sctp"
 }