diff --git a/src/shrpx_http3_upstream.cc b/src/shrpx_http3_upstream.cc
index da080c0a..92a8aad6 100644
--- a/src/shrpx_http3_upstream.cc
+++ b/src/shrpx_http3_upstream.cc
@@ -638,6 +638,7 @@ int Http3Upstream::write_streams() {
 
     bufpos += nwrite;
 
+#ifdef UDP_SEGMENT
     if (pktcnt == 0) {
       ngtcp2_path_copy(&prev_ps.path, &ps.path);
     } else if (!ngtcp2_path_eq(&prev_ps.path, &ps.path)) {
@@ -674,6 +675,23 @@ int Http3Upstream::write_streams() {
 
       return 0;
     }
+#else  // !UDP_SEGMENT
+    quic_send_packet(static_cast<UpstreamAddr *>(ps.path.user_data),
+                     ps.path.remote.addr, ps.path.remote.addrlen,
+                     ps.path.local.addr, ps.path.local.addrlen, buf.data(),
+                     bufpos - buf.data(), 0);
+
+    if (++pktcnt == max_pktcnt) {
+      ngtcp2_conn_update_pkt_tx_time(conn_, ts);
+      reset_idle_timer();
+
+      handler_->signal_write();
+
+      return 0;
+    }
+
+    bufpos = buf.data();
+#endif // !UDP_SEGMENT
   }
 
   return 0;
diff --git a/src/shrpx_quic.cc b/src/shrpx_quic.cc
index 09f0683f..a1ea2a32 100644
--- a/src/shrpx_quic.cc
+++ b/src/shrpx_quic.cc
@@ -210,8 +210,11 @@ int quic_send_packet(const UpstreamAddr *faddr, const sockaddr *remote_sa,
   msg.msg_iov = &msg_iov;
   msg.msg_iovlen = 1;
 
-  uint8_t
-      msg_ctrl[CMSG_SPACE(sizeof(uint16_t)) + CMSG_SPACE(sizeof(in6_pktinfo))];
+  uint8_t msg_ctrl[
+#ifdef UDP_SEGMENT
+      CMSG_SPACE(sizeof(uint16_t)) +
+#endif // UDP_SEGMENT
+      CMSG_SPACE(sizeof(in6_pktinfo))];
 
   memset(msg_ctrl, 0, sizeof(msg_ctrl));
 
@@ -251,6 +254,7 @@ int quic_send_packet(const UpstreamAddr *faddr, const sockaddr *remote_sa,
     assert(0);
   }
 
+#ifdef UDP_SEGMENT
   if (gso_size && datalen > gso_size) {
     controllen += CMSG_SPACE(sizeof(uint16_t));
     cm = CMSG_NXTHDR(&msg, cm);
@@ -259,6 +263,7 @@ int quic_send_packet(const UpstreamAddr *faddr, const sockaddr *remote_sa,
     cm->cmsg_len = CMSG_LEN(sizeof(uint16_t));
     *(reinterpret_cast<uint16_t *>(CMSG_DATA(cm))) = gso_size;
   }
+#endif // UDP_SEGMENT
 
   msg.msg_controllen = controllen;