diff --git a/src/main.rs b/src/main.rs
index 09d5187..e0b3ee7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,6 +6,7 @@ mod db;
 mod drive;
 mod guacd;
 mod import;
+mod migrate;
 mod oidc;
 mod protocol;
 mod pve;
@@ -151,6 +152,33 @@ enum Command {
         #[arg(long)]
         dry_run: bool,
     },
+
+    /// Copy an address-book scope subtree between configured Vault backends
+    /// (for the multi-Vault DR split). Copies entries and every folder's
+    /// `.config`; run with --dry-run first.
+    VaultMigrate {
+        /// Scope to migrate: "shared" or "instance"
+        #[arg(long)]
+        scope: String,
+        /// Source backend: "vault", "vault_shared", or "vault_local"
+        #[arg(long)]
+        from: String,
+        /// Destination backend: "vault", "vault_shared", or "vault_local"
+        #[arg(long)]
+        to: String,
+        /// Also copy ALL per-user credential secrets (users/*). This makes
+        /// those credentials shared; normally you toggle per-credential in the
+        /// My Credentials UI instead.
+        #[arg(long)]
+        users: bool,
+        /// Overwrite entries that already exist in the destination
+        /// (default: skip existing).
+        #[arg(long)]
+        overwrite: bool,
+        /// Preview without writing to the destination
+        #[arg(long)]
+        dry_run: bool,
+    },
 }
 
 #[tokio::main]
@@ -204,6 +232,17 @@ async fn main() {
             import::cmd_import_guacamole(&config, &file, &folder, &scope, &allowed_groups, dry_run)
                 .await;
         }
+        Some(Command::VaultMigrate {
+            scope,
+            from,
+            to,
+            users,
+            overwrite,
+            dry_run,
+        }) => {
+            migrate::cmd_vault_migrate(&config, &scope, &from, &to, users, overwrite, dry_run)
+                .await;
+        }
     }
 }
 
diff --git a/src/migrate.rs b/src/migrate.rs
new file mode 100644
index 0000000..a28a503
--- /dev/null
+++ b/src/migrate.rs
@@ -0,0 +1,241 @@
+//! `vault-migrate` subcommand: copy an address-book scope subtree between
+//! configured Vault backends, for the multi-Vault DR split.
+//!
+//! The scope→path layout is identical in every backend, so migration is a
+//! server-to-server copy (same scope/folder/entry identity), not a path
+//! rewrite: reading `scope=shared, folder=Foo, entry=Bar` from the source and
+//! writing it back with the same coordinates maps `<src_base>/shared/Foo/Bar`
+//! to `<dst_base>/shared/Foo/Bar`, each client applying its own mount /
+//! base_path / instance_name. Entries AND the `.config` sentinel at every
+//! folder level are copied (the latter carries allowed_groups /
+//! inherit_from_parent — dropping it would silently lose a folder's ACL).
+
+use std::sync::Arc;
+
+use crate::config::Config;
+use crate::vault::{VaultClient, VaultError};
+
+/// Run the `vault-migrate` subcommand.
+#[allow(clippy::too_many_arguments)]
+pub async fn cmd_vault_migrate(
+    config: &Config,
+    scope: &str,
+    from: &str,
+    to: &str,
+    include_users: bool,
+    overwrite: bool,
+    dry_run: bool,
+) {
+    if scope != "shared" && scope != "instance" {
+        eprintln!("Error: --scope must be \"shared\" or \"instance\"");
+        std::process::exit(1);
+    }
+    if from == to {
+        eprintln!("Error: --from and --to must name different backends");
+        std::process::exit(1);
+    }
+
+    let src = connect_named(config, from).await;
+    let dst = connect_named(config, to).await;
+
+    if dry_run {
+        println!(
+            "[DRY RUN] Copy {} scope: {} -> {} (nothing will be written)\n",
+            scope, from, to
+        );
+    } else {
+        println!("Copying {} scope: {} -> {}\n", scope, from, to);
+    }
+
+    // BFS-collect every folder path in the scope subtree (top-level first, so
+    // ancestors are written before descendants).
+    let top = match src.list_folders_in_scope(scope).await {
+        Ok(f) => f,
+        Err(e) => {
+            eprintln!(
+                "Error listing folders in {} scope on '{}': {}",
+                scope, from, e
+            );
+            std::process::exit(1);
+        }
+    };
+    let mut folder_paths: Vec<String> = top.into_iter().map(|f| f.path.unwrap_or(f.name)).collect();
+    let mut i = 0;
+    while i < folder_paths.len() {
+        let path = folder_paths[i].clone();
+        if let Ok(subs) = src.list_subfolders(scope, &path).await {
+            for s in subs {
+                folder_paths.push(s.path.unwrap_or_else(|| format!("{}/{}", path, s.name)));
+            }
+        }
+        i += 1;
+    }
+
+    let mut folders_done = 0usize;
+    let mut entries_copied = 0usize;
+    let mut entries_skipped = 0usize;
+    let mut failures = 0usize;
+
+    for path in &folder_paths {
+        folders_done += 1;
+
+        // Copy the folder's .config sentinel (if any).
+        match src.get_folder_config(scope, path).await {
+            Ok(cfg) => {
+                if dry_run {
+                    println!("  [config] {}", path);
+                } else if let Err(e) = dst.put_folder_config(scope, path, &cfg).await {
+                    eprintln!("  Warning: write .config for '{}' failed: {}", path, e);
+                    failures += 1;
+                }
+            }
+            Err(VaultError::NotFound) => {}
+            Err(e) => eprintln!("  Warning: read .config for '{}' failed: {}", path, e),
+        }
+
+        // Copy entries.
+        let entries = src.list_entries(scope, path).await.unwrap_or_default();
+        for name in &entries {
+            // Skip existing unless --overwrite (the existence probe is only
+            // meaningful for a real write).
+            if !overwrite && !dry_run {
+                match dst.get_entry(scope, path, name).await {
+                    Ok(_) => {
+                        println!("  skip (exists): {}/{}", path, name);
+                        entries_skipped += 1;
+                        continue;
+                    }
+                    Err(VaultError::NotFound) => {}
+                    Err(_) => {} // fall through and try the copy
+                }
+            }
+
+            match src.get_entry(scope, path, name).await {
+                Ok(entry) => {
+                    if dry_run {
+                        println!("  [entry]  {}/{}", path, name);
+                        entries_copied += 1;
+                    } else {
+                        match dst.put_entry(scope, path, name, &entry).await {
+                            Ok(()) => {
+                                println!("  copied:  {}/{}", path, name);
+                                entries_copied += 1;
+                            }
+                            Err(e) => {
+                                eprintln!("  FAILED:  {}/{} — {}", path, name, e);
+                                failures += 1;
+                            }
+                        }
+                    }
+                }
+                Err(e) => {
+                    eprintln!("  FAILED to read {}/{}: {}", path, name, e);
+                    failures += 1;
+                }
+            }
+        }
+    }
+
+    // Optionally copy every per-user credential secret (users/*).
+    let mut users_copied = 0usize;
+    if include_users {
+        match src.list_user_keys().await {
+            Ok(keys) => {
+                for key in &keys {
+                    match src.get_user_credentials_by_key(key).await {
+                        Ok(creds) => {
+                            if dry_run {
+                                println!("  [users]  {} ({} vars)", key, creds.len());
+                                users_copied += 1;
+                            } else {
+                                match dst.put_user_credentials_by_key(key, &creds).await {
+                                    Ok(()) => {
+                                        println!("  copied:  users/{}", key);
+                                        users_copied += 1;
+                                    }
+                                    Err(e) => {
+                                        eprintln!("  FAILED:  users/{} — {}", key, e);
+                                        failures += 1;
+                                    }
+                                }
+                            }
+                        }
+                        Err(e) => eprintln!("  FAILED to read users/{}: {}", key, e),
+                    }
+                }
+            }
+            Err(e) => eprintln!("Warning: could not list users on '{}': {}", from, e),
+        }
+    }
+
+    let verb = if dry_run { "would copy" } else { "copied" };
+    println!(
+        "\n{} {} folders, {} entries {} ({} skipped){}{}.",
+        if dry_run { "[DRY RUN]" } else { "Done:" },
+        folders_done,
+        entries_copied,
+        verb,
+        entries_skipped,
+        if include_users {
+            format!(", {} user credential secrets", users_copied)
+        } else {
+            String::new()
+        },
+        if failures > 0 {
+            format!(", {} FAILURES", failures)
+        } else {
+            String::new()
+        }
+    );
+    if dry_run {
+        println!("Re-run without --dry-run to perform the copy.");
+    }
+    if failures > 0 {
+        std::process::exit(1);
+    }
+}
+
+/// Resolve a named backend (`vault` / `vault_shared` / `vault_local`) from
+/// config, read its secret ID from the matching env var, and connect. Exits
+/// the process with a clear message on any misconfiguration.
+async fn connect_named(config: &Config, name: &str) -> Arc<VaultClient> {
+    let (vault_config, env_var) = match name {
+        "vault" => (config.vault.as_ref(), "VAULT_SECRET_ID"),
+        "vault_shared" => (config.vault_shared.as_ref(), "VAULT_SHARED_SECRET_ID"),
+        "vault_local" => (config.vault_local.as_ref(), "VAULT_LOCAL_SECRET_ID"),
+        _ => {
+            eprintln!(
+                "Error: unknown backend '{}' (use vault, vault_shared, or vault_local)",
+                name
+            );
+            std::process::exit(1);
+        }
+    };
+
+    let vault_config = match vault_config {
+        Some(vc) => vc,
+        None => {
+            eprintln!("Error: backend '{}' is not configured in config.toml", name);
+            std::process::exit(1);
+        }
+    };
+
+    let secret_id = match std::env::var(env_var) {
+        Ok(s) if !s.is_empty() => s,
+        _ => {
+            eprintln!("Error: {} env var required for backend '{}'", env_var, name);
+            std::process::exit(1);
+        }
+    };
+
+    match VaultClient::new(vault_config, &secret_id).await {
+        Ok(c) => Arc::new(c),
+        Err(e) => {
+            eprintln!(
+                "Error connecting to backend '{}' ({}): {}",
+                name, vault_config.addr, e
+            );
+            std::process::exit(1);
+        }
+    }
+}
diff --git a/src/vault.rs b/src/vault.rs
index 2812a45..29dc485 100644
--- a/src/vault.rs
+++ b/src/vault.rs
@@ -1158,7 +1158,27 @@ impl VaultClient {
         &self,
         email: &str,
     ) -> Result<HashMap<String, String>, VaultError> {
-        let key = sanitize_email_key(email);
+        self.get_user_credentials_by_key(&sanitize_email_key(email))
+            .await
+    }
+
+    /// Write a user's credential variables to Vault (full replace).
+    /// Path: `<base_path>/users/<sanitized_email>`
+    pub async fn put_user_credentials(
+        &self,
+        email: &str,
+        creds: &HashMap<String, String>,
+    ) -> Result<(), VaultError> {
+        self.put_user_credentials_by_key(&sanitize_email_key(email), creds)
+            .await
+    }
+
+    /// Read credential variables by the already-sanitised users key. Used by
+    /// `vault-migrate` (which enumerates raw keys and must not re-sanitise).
+    pub async fn get_user_credentials_by_key(
+        &self,
+        key: &str,
+    ) -> Result<HashMap<String, String>, VaultError> {
         let path = format!("/v1/{}/data/{}/users/{}", self.mount, self.base_path, key);
         let resp = self.request(reqwest::Method::GET, &path, None).await?;
 
@@ -1185,14 +1205,13 @@ impl VaultClient {
         }
     }
 
-    /// Write a user's credential variables to Vault (full replace).
-    /// Path: `<base_path>/users/<sanitized_email>`
-    pub async fn put_user_credentials(
+    /// Write credential variables by the already-sanitised users key (full
+    /// replace). Companion to [`get_user_credentials_by_key`] for migration.
+    pub async fn put_user_credentials_by_key(
         &self,
-        email: &str,
+        key: &str,
         creds: &HashMap<String, String>,
     ) -> Result<(), VaultError> {
-        let key = sanitize_email_key(email);
         let path = format!("/v1/{}/data/{}/users/{}", self.mount, self.base_path, key);
         let body = serde_json::json!({ "data": creds });
         let resp = self
@@ -1212,6 +1231,17 @@ impl VaultClient {
         }
     }
 
+    /// List the raw key names under `<base_path>/users/` (each a sanitised
+    /// email). Empty when no credentials have been stored yet.
+    pub async fn list_user_keys(&self) -> Result<Vec<String>, VaultError> {
+        let path = format!("/v1/{}/metadata/{}/users/", self.mount, self.base_path);
+        match self.kv_list(&path).await {
+            Ok(keys) => Ok(keys.into_iter().filter(|k| !k.ends_with('/')).collect()),
+            Err(VaultError::NotFound) => Ok(Vec::new()),
+            Err(e) => Err(e),
+        }
+    }
+
     /// Delete a user's credential variables from Vault.
     #[allow(dead_code)] // Will be used by admin endpoint
     pub async fn delete_user_credentials(&self, email: &str) -> Result<(), VaultError> {