diff --git a/Cargo.toml b/Cargo.toml
index 66be539..4604153 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,13 +19,18 @@ travis-ci = { repository = "dunmatt/no-std-net" }
 
 [dependencies]
 serde = { version = "^1", default-features = false, optional = true }
+defmt = { version = "0.3", default-features = false, optional = true}
 
 [dev-dependencies]
 serde_test = "^1"
 
 [features]
+default = ["defmt"]
+
 # Makes the library act as a facade to std::net types
 std = []
+# defmt impls
+defmt = ["dep:defmt"]
 # Like `#![feature(ip)]`, see https://github.com/rust-lang/rust/issues/27709
 unstable_ip = []
 # Deprecated. Does nothing.
diff --git a/src/addr.rs b/src/addr.rs
index 6ef9f72..2d881d7 100644
--- a/src/addr.rs
+++ b/src/addr.rs
@@ -35,6 +35,7 @@ use super::{IpAddr, Ipv4Addr, Ipv6Addr};
 /// assert_eq!(socket.is_ipv4(), true);
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum SocketAddr {
     /// An IPv4 socket address.
     V4(SocketAddrV4),
@@ -64,6 +65,7 @@ pub enum SocketAddr {
 /// assert_eq!(socket.port(), 8080);
 /// ```
 #[derive(Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct SocketAddrV4 {
     addr: Ipv4Addr,
     port: u16,
@@ -92,6 +94,7 @@ pub struct SocketAddrV4 {
 /// assert_eq!(socket.port(), 8080);
 /// ```
 #[derive(Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct SocketAddrV6 {
     addr: Ipv6Addr,
     port: u16,
diff --git a/src/ip.rs b/src/ip.rs
index 96d76b6..c3a833b 100644
--- a/src/ip.rs
+++ b/src/ip.rs
@@ -67,6 +67,7 @@ pub enum IpAddr {
 /// assert_eq!(localhost.is_loopback(), true);
 /// ```
 #[derive(Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Ipv4Addr {
     // Octets stored in transmit order.
     inner: [u8; 4],
@@ -101,6 +102,7 @@ pub struct Ipv4Addr {
 /// assert_eq!(localhost.is_loopback(), true);
 /// ```
 #[derive(Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Ipv6Addr {
     // Octets stored in transmit order.
     inner: [u8; 16],