diff --git a/Cargo.lock b/Cargo.lock
index 87adc5e2b..458266207 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3435,6 +3435,7 @@ dependencies = [
  "rustls-pemfile",
  "serde",
  "serde_json",
+ "serde_yml",
  "tar",
  "temp-env",
  "tempfile",
diff --git a/crates/openshell-cli/Cargo.toml b/crates/openshell-cli/Cargo.toml
index 7dc0c0f22..543fed6c3 100644
--- a/crates/openshell-cli/Cargo.toml
+++ b/crates/openshell-cli/Cargo.toml
@@ -23,6 +23,7 @@ openshell-prover = { path = "../openshell-prover" }
 openshell-tui = { path = "../openshell-tui" }
 serde = { workspace = true }
 serde_json = { workspace = true }
+serde_yml = { workspace = true }
 prost-types = { workspace = true }
 
 # Async runtime
diff --git a/crates/openshell-cli/src/main.rs b/crates/openshell-cli/src/main.rs
index ca242be32..62a7b0ec1 100644
--- a/crates/openshell-cli/src/main.rs
+++ b/crates/openshell-cli/src/main.rs
@@ -647,13 +647,13 @@ fn normalize_completion_script(output: Vec<u8>, executable: &std::path::Path) ->
 }
 
 #[derive(Clone, Debug, ValueEnum)]
-enum ProviderProfileOutput {
+enum OutputFormat {
     Table,
     Yaml,
     Json,
 }
 
-impl ProviderProfileOutput {
+impl OutputFormat {
     fn as_str(&self) -> &'static str {
         match self {
             Self::Table => "table",
@@ -736,8 +736,8 @@ enum ProviderCommands {
     #[command(help_template = LEAF_HELP_TEMPLATE, next_help_heading = "FLAGS")]
     ListProfiles {
         /// Output format.
-        #[arg(short = 'o', long = "output", value_enum, default_value_t = ProviderProfileOutput::Table)]
-        output: ProviderProfileOutput,
+        #[arg(short = 'o', long = "output", value_enum, default_value_t = OutputFormat::Table)]
+        output: OutputFormat,
     },
 
     /// Manage provider profiles.
@@ -786,8 +786,8 @@ enum ProviderProfileCommands {
         id: String,
 
         /// Output format.
-        #[arg(short = 'o', long = "output", value_enum, default_value_t = ProviderProfileOutput::Yaml)]
-        output: ProviderProfileOutput,
+        #[arg(short = 'o', long = "output", value_enum, default_value_t = OutputFormat::Yaml)]
+        output: OutputFormat,
     },
 
     /// Import provider profiles from a file or directory.
@@ -1167,16 +1167,20 @@ enum SandboxCommands {
         offset: u32,
 
         /// Print only sandbox ids (one per line).
-        #[arg(long, conflicts_with = "names")]
+        #[arg(long, conflicts_with_all = ["names", "output"])]
         ids: bool,
 
         /// Print only sandbox names (one per line).
-        #[arg(long, conflicts_with = "ids")]
+        #[arg(long, conflicts_with_all = ["ids", "output"])]
         names: bool,
 
         /// Filter sandboxes by label selector (key1=value1,key2=value2).
         #[arg(long)]
         selector: Option<String>,
+
+        /// Output format.
+        #[arg(short = 'o', long = "output", value_enum, default_value_t = OutputFormat::Table, conflicts_with_all = ["ids", "names"])]
+        output: OutputFormat,
     },
 
     /// Delete a sandbox by name.
@@ -2527,6 +2531,7 @@ async fn main() -> Result<()> {
                             ids,
                             names,
                             selector,
+                            output,
                         } => {
                             run::sandbox_list(
                                 endpoint,
@@ -2535,6 +2540,7 @@ async fn main() -> Result<()> {
                                 ids,
                                 names,
                                 selector.as_deref(),
+                                output.as_str(),
                                 &tls,
                             )
                             .await?;
@@ -3398,7 +3404,7 @@ mod tests {
             cli.command,
             Some(Commands::Provider {
                 command: Some(ProviderCommands::ListProfiles {
-                    output: ProviderProfileOutput::Table
+                    output: OutputFormat::Table
                 })
             })
         ));
@@ -3413,7 +3419,7 @@ mod tests {
             cli.command,
             Some(Commands::Provider {
                 command: Some(ProviderCommands::ListProfiles {
-                    output: ProviderProfileOutput::Json
+                    output: OutputFormat::Json
                 })
             })
         ));
@@ -3436,7 +3442,7 @@ mod tests {
             Some(Commands::Provider {
                 command: Some(ProviderCommands::Profile(ProviderProfileCommands::Export {
                     id,
-                    output: ProviderProfileOutput::Yaml
+                    output: OutputFormat::Yaml
                 }))
             }) if id == "custom-api"
         ));
@@ -3473,6 +3479,66 @@ mod tests {
         ));
     }
 
+    #[test]
+    fn sandbox_list_default_output_is_table() {
+        let cli = Cli::try_parse_from(["openshell", "sandbox", "list"])
+            .expect("sandbox list should parse");
+
+        assert!(matches!(
+            cli.command,
+            Some(Commands::Sandbox {
+                command: Some(SandboxCommands::List {
+                    output: OutputFormat::Table,
+                    ..
+                })
+            })
+        ));
+    }
+
+    #[test]
+    fn sandbox_list_accepts_output_json() {
+        let cli = Cli::try_parse_from(["openshell", "sandbox", "list", "-o", "json"])
+            .expect("sandbox list -o json should parse");
+
+        assert!(matches!(
+            cli.command,
+            Some(Commands::Sandbox {
+                command: Some(SandboxCommands::List {
+                    output: OutputFormat::Json,
+                    ..
+                })
+            })
+        ));
+    }
+
+    #[test]
+    fn sandbox_list_accepts_output_yaml() {
+        let cli = Cli::try_parse_from(["openshell", "sandbox", "list", "-o", "yaml"])
+            .expect("sandbox list -o yaml should parse");
+
+        assert!(matches!(
+            cli.command,
+            Some(Commands::Sandbox {
+                command: Some(SandboxCommands::List {
+                    output: OutputFormat::Yaml,
+                    ..
+                })
+            })
+        ));
+    }
+
+    #[test]
+    fn sandbox_list_json_conflicts_with_ids() {
+        let result = Cli::try_parse_from(["openshell", "sandbox", "list", "-o", "json", "--ids"]);
+        assert!(result.is_err(), "--ids and -o json should conflict");
+    }
+
+    #[test]
+    fn sandbox_list_json_conflicts_with_names() {
+        let result = Cli::try_parse_from(["openshell", "sandbox", "list", "-o", "json", "--names"]);
+        assert!(result.is_err(), "--names and -o json should conflict");
+    }
+
     #[test]
     fn provider_create_accepts_custom_profile_type_ids() {
         let cli = Cli::try_parse_from([
diff --git a/crates/openshell-cli/src/run.rs b/crates/openshell-cli/src/run.rs
index 198cb4b0a..30025a14a 100644
--- a/crates/openshell-cli/src/run.rs
+++ b/crates/openshell-cli/src/run.rs
@@ -3045,6 +3045,7 @@ fn print_sandbox_policy(policy: &SandboxPolicy) {
 }
 
 /// List sandboxes.
+#[allow(clippy::too_many_arguments)]
 pub async fn sandbox_list(
     server: &str,
     limit: u32,
@@ -3052,6 +3053,7 @@ pub async fn sandbox_list(
     ids_only: bool,
     names_only: bool,
     label_selector: Option<&str>,
+    output: &str,
     tls: &TlsOptions,
 ) -> Result<()> {
     let mut client = grpc_client(server, tls).await?;
@@ -3066,6 +3068,25 @@ pub async fn sandbox_list(
         .into_diagnostic()?;
 
     let sandboxes = response.into_inner().sandboxes;
+
+    match output {
+        "json" => {
+            let items: Vec<serde_json::Value> = sandboxes.iter().map(sandbox_to_json).collect();
+            println!(
+                "{}",
+                serde_json::to_string_pretty(&items).into_diagnostic()?
+            );
+            return Ok(());
+        }
+        "yaml" => {
+            let items: Vec<serde_json::Value> = sandboxes.iter().map(sandbox_to_json).collect();
+            print!("{}", serde_yml::to_string(&items).into_diagnostic()?);
+            return Ok(());
+        }
+        "table" => {}
+        _ => return Err(miette!("unsupported output format: {output}")),
+    }
+
     if sandboxes.is_empty() {
         if !ids_only && !names_only {
             println!("No sandboxes found.");
@@ -3126,6 +3147,19 @@ pub async fn sandbox_list(
     Ok(())
 }
 
+fn sandbox_to_json(sandbox: &Sandbox) -> serde_json::Value {
+    let meta = sandbox.metadata.as_ref();
+    let labels = meta.map_or_else(|| serde_json::json!({}), |m| serde_json::json!(m.labels));
+    serde_json::json!({
+        "id": sandbox.object_id(),
+        "name": sandbox.object_name(),
+        "labels": labels,
+        "created_at": format_epoch_ms(meta.map_or(0, |m| m.created_at_ms)),
+        "phase": phase_name(sandbox.phase),
+        "current_policy_version": sandbox.current_policy_version,
+    })
+}
+
 pub async fn sandbox_provider_list(server: &str, name: &str, tls: &TlsOptions) -> Result<()> {
     let mut client = grpc_client(server, tls).await?;
     let response = client
diff --git a/docs/sandboxes/manage-sandboxes.mdx b/docs/sandboxes/manage-sandboxes.mdx
index d8752c261..a62f57bf5 100644
--- a/docs/sandboxes/manage-sandboxes.mdx
+++ b/docs/sandboxes/manage-sandboxes.mdx
@@ -211,6 +211,13 @@ Filter the list by labels when you want a narrower view:
 openshell sandbox list --selector team=platform
 ```
 
+Use `-o json` or `-o yaml` for machine-readable output:
+
+```shell
+openshell sandbox list -o json
+openshell sandbox list -o yaml
+```
+
 Get detailed information about a specific sandbox. The output lists **Policy source** (`sandbox` or `global`), **Revision** (the active policy’s row version for that source), and the formatted active policy YAML:
 
 ```shell