diff --git a/lib/connect.c b/lib/connect.c
index a50c09a338..a0f1f17400 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -1638,6 +1638,24 @@ CURLcode Curl_socket(struct Curl_easy *data,
   if(conn->transport == TRNSPRT_QUIC) {
     /* QUIC sockets need to be nonblocking */
     (void)curlx_nonblock(*sockfd, TRUE);
+    switch(addr->family) {
+#if defined(__linux__) && defined(IP_MTU_DISCOVER)
+    case AF_INET: {
+      int val = IP_PMTUDISC_DO;
+      (void)setsockopt(*sockfd, IPPROTO_IP, IP_MTU_DISCOVER, &val,
+                       sizeof(val));
+      break;
+    }
+#endif
+#if defined(__linux__) && defined(IPV6_MTU_DISCOVER)
+    case AF_INET6: {
+      int val = IPV6_PMTUDISC_DO;
+      (void)setsockopt(*sockfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, &val,
+                       sizeof(val));
+      break;
+    }
+#endif
+    }
   }
 
 #if defined(ENABLE_IPV6) && defined(HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID)
diff --git a/lib/vquic/ngtcp2.c b/lib/vquic/ngtcp2.c
index f2acce123b..239e1d160f 100644
--- a/lib/vquic/ngtcp2.c
+++ b/lib/vquic/ngtcp2.c
@@ -1814,7 +1814,7 @@ static CURLcode ng_flush_egress(struct Curl_easy *data,
   int rv;
   ssize_t sent;
   ngtcp2_ssize outlen;
-  uint8_t out[NGTCP2_MAX_UDP_PAYLOAD_SIZE];
+  uint8_t out[NGTCP2_MAX_PMTUD_UDP_PAYLOAD_SIZE];
   ngtcp2_path_storage ps;
   ngtcp2_tstamp ts = timestamp();
   ngtcp2_tstamp expiry;
@@ -1924,7 +1924,10 @@ static CURLcode ng_flush_egress(struct Curl_easy *data,
       else {
         failf(data, "send() returned %zd (errno %d)", sent,
               SOCKERRNO);
-        return CURLE_SEND_ERROR;
+        if(SOCKERRNO != EMSGSIZE) {
+          return CURLE_SEND_ERROR;
+        }
+        /* UDP datagram is too large; caused by PMTUD. Just let it be lost. */
       }
     }
   }