diff --git a/quinn-proto/src/connection/datagrams.rs b/quinn-proto/src/connection/datagrams.rs
index d2698fd14..1277e8648 100644
--- a/quinn-proto/src/connection/datagrams.rs
+++ b/quinn-proto/src/connection/datagrams.rs
@@ -75,6 +75,17 @@ impl<'a> Datagrams<'a> {
     pub fn recv(&mut self) -> Option<Bytes> {
         self.conn.datagrams.recv()
     }
+
+    /// Bytes available in the outgoing datagram buffer
+    ///
+    /// When greater than zero, [`send`](Self::send)ing a datagram of at most this size is
+    /// guaranteed not to cause older datagrams to be dropped.
+    pub fn send_buffer_space(&self) -> usize {
+        self.conn
+            .config
+            .datagram_send_buffer_size
+            .saturating_sub(self.conn.datagrams.outgoing_total)
+    }
 }
 
 #[derive(Default)]
diff --git a/quinn/src/connection.rs b/quinn/src/connection.rs
index 1636a5a47..e370c09d8 100644
--- a/quinn/src/connection.rs
+++ b/quinn/src/connection.rs
@@ -403,6 +403,19 @@ impl Connection {
             .max_size()
     }
 
+    /// Bytes available in the outgoing datagram buffer
+    ///
+    /// When greater than zero, calling [`send_datagram()`](Self::send_datagram) with a datagram of
+    /// at most this size is guaranteed not to cause older datagrams to be dropped.
+    pub fn datagram_send_buffer_space(&self) -> usize {
+        self.0
+            .state
+            .lock("datagram_send_buffer_space")
+            .inner
+            .datagrams()
+            .send_buffer_space()
+    }
+
     /// The peer's UDP address
     ///
     /// If `ServerConfig::migration` is `true`, clients may change addresses at will, e.g. when