diff --git a/src/build.rs b/src/build.rs
index 4d8c95d..23ef07d 100644
--- a/src/build.rs
+++ b/src/build.rs
@@ -40,6 +40,7 @@ pub struct BuildBuilder<'a> {
     krate: &'a Crate,
     sandbox: SandboxBuilder,
     patches: Vec<CratePatch>,
+    extra_cargo_args: Vec<String>,
 }
 
 impl BuildBuilder<'_> {
@@ -107,6 +108,36 @@ impl BuildBuilder<'_> {
         self
     }
 
+    /// Add extra arguments passed to cargo commands during the prepare phase
+    /// (manifest validation, lockfile generation, dependency fetching).
+    ///
+    /// This is useful for passing unstable cargo flags (e.g. `-Zbindeps`) that
+    /// are required for cargo to parse the crate's manifest.
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// # use rustwide::{WorkspaceBuilder, Toolchain, Crate, cmd::SandboxBuilder};
+    /// # use std::error::Error;
+    /// # fn main() -> anyhow::Result<(), Box<dyn Error>> {
+    /// # let workspace = WorkspaceBuilder::new("".as_ref(), "").init()?;
+    /// # let toolchain = Toolchain::dist("");
+    /// # let krate = Crate::local("".as_ref());
+    /// # let sandbox = SandboxBuilder::new();
+    /// let mut build_dir = workspace.build_dir("foo");
+    /// build_dir.build(&toolchain, &krate, sandbox)
+    ///     .extra_cargo_args(vec!["-Zbindeps".into()])
+    ///     .run(|build| {
+    ///         build.cargo().args(&["test", "--all"]).run()?;
+    ///         Ok(())
+    ///     })?;
+    /// # Ok(())
+    /// # }
+    pub fn extra_cargo_args(mut self, args: Vec<String>) -> Self {
+        self.extra_cargo_args = args;
+        self
+    }
+
     /// Run a sandboxed build of the provided crate with the provided toolchain. The closure will
     /// be provided an instance of [`Build`](struct.Build.html) that allows spawning new processes
     /// inside the sandbox.
@@ -131,8 +162,14 @@ impl BuildBuilder<'_> {
     /// # Ok(())
     /// # }
     pub fn run<R, F: FnOnce(&Build) -> anyhow::Result<R>>(self, f: F) -> anyhow::Result<R> {
-        self.build_dir
-            .run(self.toolchain, self.krate, self.sandbox, self.patches, f)
+        self.build_dir.run(
+            self.toolchain,
+            self.krate,
+            self.sandbox,
+            self.patches,
+            self.extra_cargo_args,
+            f,
+        )
     }
 }
 
@@ -177,6 +214,7 @@ impl BuildDirectory {
             krate,
             sandbox,
             patches: Vec::new(),
+            extra_cargo_args: Vec::new(),
         }
     }
 
@@ -186,6 +224,7 @@ impl BuildDirectory {
         krate: &Crate,
         sandbox: SandboxBuilder,
         patches: Vec<CratePatch>,
+        extra_cargo_args: Vec<String>,
         f: F,
     ) -> anyhow::Result<R> {
         let source_dir = self.source_dir();
@@ -193,7 +232,14 @@ impl BuildDirectory {
             crate::utils::remove_dir_all(&source_dir)?;
         }
 
-        let mut prepare = Prepare::new(&self.workspace, toolchain, krate, &source_dir, patches);
+        let mut prepare = Prepare::new(
+            &self.workspace,
+            toolchain,
+            krate,
+            &source_dir,
+            patches,
+            extra_cargo_args,
+        );
         prepare.prepare().map_err(|err| {
             if err.downcast_ref::<PrepareError>().is_none() {
                 err.context(PrepareError::Uncategorized)
@@ -333,6 +379,7 @@ impl<'ws> Build<'ws> {
             self.toolchain,
             &self.host_source_dir(),
             targets,
+            &[],
         )
     }
 }
diff --git a/src/prepare.rs b/src/prepare.rs
index a4908bc..e8b9aee 100644
--- a/src/prepare.rs
+++ b/src/prepare.rs
@@ -14,6 +14,7 @@ pub(crate) struct Prepare<'a> {
     krate: &'a Crate,
     source_dir: &'a Path,
     patches: Vec<CratePatch>,
+    extra_cargo_args: Vec<String>,
 }
 
 impl<'a> Prepare<'a> {
@@ -23,6 +24,7 @@ impl<'a> Prepare<'a> {
         krate: &'a Crate,
         source_dir: &'a Path,
         patches: Vec<CratePatch>,
+        extra_cargo_args: Vec<String>,
     ) -> Self {
         Self {
             workspace,
@@ -30,6 +32,7 @@ impl<'a> Prepare<'a> {
             krate,
             source_dir,
             patches,
+            extra_cargo_args,
         }
     }
 
@@ -57,6 +60,7 @@ impl<'a> Prepare<'a> {
 
         let res = Command::new(self.workspace, self.toolchain.cargo())
             .args(&["metadata", "--manifest-path", "Cargo.toml", "--no-deps"])
+            .args(&self.extra_cargo_args)
             .cd(self.source_dir)
             .log_output(false)
             .run();
@@ -101,11 +105,9 @@ impl<'a> Prepare<'a> {
             return Ok(());
         }
 
-        let mut cmd = Command::new(self.workspace, self.toolchain.cargo()).args(&[
-            "generate-lockfile",
-            "--manifest-path",
-            "Cargo.toml",
-        ]);
+        let mut cmd = Command::new(self.workspace, self.toolchain.cargo())
+            .args(&["generate-lockfile", "--manifest-path", "Cargo.toml"])
+            .args(&self.extra_cargo_args);
         if !self.workspace.fetch_registry_index_during_builds() {
             cmd = cmd
                 .args(&["-Zno-index-update"])
@@ -116,7 +118,13 @@ impl<'a> Prepare<'a> {
     }
 
     fn fetch_deps(&mut self) -> anyhow::Result<()> {
-        fetch_deps(self.workspace, self.toolchain, self.source_dir, &[])
+        fetch_deps(
+            self.workspace,
+            self.toolchain,
+            self.source_dir,
+            &[],
+            &self.extra_cargo_args,
+        )
     }
 }
 
@@ -125,9 +133,11 @@ pub(crate) fn fetch_deps(
     toolchain: &Toolchain,
     source_dir: &Path,
     fetch_build_std_targets: &[&str],
+    extra_cargo_args: &[String],
 ) -> anyhow::Result<()> {
     let mut cmd = Command::new(workspace, toolchain.cargo())
         .args(&["fetch", "--manifest-path", "Cargo.toml"])
+        .args(extra_cargo_args)
         .cd(source_dir);
     // Pass `-Zbuild-std` in case a build in the sandbox wants to use it;
     // build-std has to have the source for libstd's dependencies available.
diff --git a/tests/buildtest/mod.rs b/tests/buildtest/mod.rs
index d27f9bb..8d88e45 100644
--- a/tests/buildtest/mod.rs
+++ b/tests/buildtest/mod.rs
@@ -247,6 +247,37 @@ fn test_cargo_workspace() {
     });
 }
 
+#[test]
+fn test_extra_cargo_args() {
+    runner::run("hello-world", |run| {
+        run.build(SandboxBuilder::new().enable_networking(false), |builder| {
+            builder
+                .extra_cargo_args(vec!["--quiet".into()])
+                .run(|build| {
+                    build.cargo().args(&["run"]).run()?;
+                    Ok(())
+                })
+        })?;
+        Ok(())
+    });
+}
+
+#[test]
+fn test_extra_cargo_args_invalid() {
+    runner::run("hello-world", |run| {
+        let res = run.build(SandboxBuilder::new().enable_networking(false), |builder| {
+            builder
+                .extra_cargo_args(vec!["--invalid-flag-that-does-not-exist".into()])
+                .run(|_build| Ok(()))
+        });
+        assert!(
+            res.is_err(),
+            "expected extra cargo args to cause a prepare failure"
+        );
+        Ok(())
+    });
+}
+
 test_prepare_error!(
     test_missing_cargotoml,
     "missing-cargotoml",