diff --git a/rp2040-hal/Cargo.toml b/rp2040-hal/Cargo.toml
index 6ea6523..7b29844 100644
--- a/rp2040-hal/Cargo.toml
+++ b/rp2040-hal/Cargo.toml
@@ -30,6 +30,8 @@ critical-section = { version = "0.2.4", features = ["custom-impl"] }
 futures = { version = "0.3", default-features = false, optional = true }
 chrono = { version = "0.4", default-features = false, optional = true }
 
+defmt = { version = ">=0.2.0, <0.4", optional = true }
+
 [dev-dependencies]
 cortex-m-rt = "0.7"
 panic-halt = "0.2.0"
diff --git a/rp2040-hal/src/i2c.rs b/rp2040-hal/src/i2c.rs
index 463f287..6ceefe2 100644
--- a/rp2040-hal/src/i2c.rs
+++ b/rp2040-hal/src/i2c.rs
@@ -66,6 +66,7 @@ pub mod peripheral;
 /// I2C error
 #[non_exhaustive]
 #[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum Error {
     /// I2C abort with error
     Abort(u32),