diff --git a/CHANGELOG.md b/CHANGELOG.md
index 02d5b3186022e3a0502f28c77133a2525dfe172d..009124ea658c17011cd9d2bd556a8aec3641d1b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+- Change default optimizations pass to focus on code size - [#305](https://github.com/paritytech/cargo-contract/pull/305)
+
 ## [0.12.1] - 2021-04-25
 
 ### Added
diff --git a/src/cmd/build.rs b/src/cmd/build.rs
index fbbc6514fc7a6a575d9b9d463dc8e74b4e7ba106..911d615c1438bc2ab1ebb089926d9998adee5eec 100644
--- a/src/cmd/build.rs
+++ b/src/cmd/build.rs
@@ -81,7 +81,7 @@ pub struct BuildCommand {
     ///
     /// - `z`, execute default optimization passes, super-focusing on code size
     ///
-    /// - The default value is `3`
+    /// - The default value is `z`
     ///
     /// - It is possible to define the number of optimization passes in the
     ///   `[package.metadata.contract]` of your `Cargo.toml` as e.g. `optimization-passes = "3"`.
diff --git a/src/main.rs b/src/main.rs
index a74056b927bf0a637fc95bd52cc8712b6bb9d66a..e38abe9b0b3ab63f19787ba91600a5b75d8ceaa0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -128,7 +128,7 @@ impl Display for OptimizationPasses {
 
 impl Default for OptimizationPasses {
     fn default() -> OptimizationPasses {
-        OptimizationPasses::Three
+        OptimizationPasses::Z
     }
 }