diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ee06b1a8d..bd31638b1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -131,6 +131,10 @@ jobs:
           workspaces: ". -> target/dev"
       - name: tmpfs headroom
         run: df -h /dev/shm && free -m
+      - name: rbitcoin-node signet datadir regressions
+        run: |
+          cargo test -p rbitcoin-node custom_signet_datadir_appends_challenge -- --nocapture --test-threads=1
+          cargo test -p rbitcoin-node default_signet_datadir_uses_builtin_challenge -- --nocapture --test-threads=1
       - name: cargo test
         run: cargo test --workspace
 
diff --git a/crates/rbitcoin-node/src/cli.rs b/crates/rbitcoin-node/src/cli.rs
index 35963392c..89767996c 100644
--- a/crates/rbitcoin-node/src/cli.rs
+++ b/crates/rbitcoin-node/src/cli.rs
@@ -263,7 +263,7 @@ where
                     "rbitcoin-node {} on {} datadir={}",
                     env!("CARGO_PKG_VERSION"),
                     handle.network_name(),
-                    handle.config.datadir.path().display()
+                    handle.config.datadir_path().display()
                 );
                 if std::env::var_os("RBITCOIN_TEST_DROP_STORE").is_some() {
                     let _ = std::fs::remove_dir_all(handle.config.store_path());
diff --git a/crates/rbitcoin-node/src/config.rs b/crates/rbitcoin-node/src/config.rs
index 355ebee9d..862269f6e 100644
--- a/crates/rbitcoin-node/src/config.rs
+++ b/crates/rbitcoin-node/src/config.rs
@@ -1,5 +1,5 @@
 use crate::error::NodeError;
-use bitcoin::hex::FromHex;
+use bitcoin::hex::{DisplayHex, FromHex};
 use bitcoin::ScriptBuf;
 use rbitcoin_consensus::{default_milestone_anchor, ChainParams, Milestone};
 use rbitcoin_esplora::EsploraListen;
@@ -476,6 +476,32 @@ impl NodeConfig {
         self
     }
 
+    /// Datadir resolved for the active chain.
+    ///
+    /// Custom signet keeps its own `signet/<challenge>` tree so peers and
+    /// store state do not collide with other signet challenges. Plain signet
+    /// uses the network default challenge.
+    pub fn datadir_path(&self) -> PathBuf {
+        let root = self.datadir.path();
+        if self.network != Network::Signet {
+            return root.to_path_buf();
+        }
+        let challenge = self.signet_challenge.as_ref().map_or_else(
+            || {
+                rbitcoin_consensus::ChainParams::signet()
+                    .signet_challenge
+                    .expect("default signet challenge")
+            },
+            Clone::clone,
+        );
+        let challenge = challenge.as_bytes().to_lower_hex_string();
+        let custom = Path::new("signet").join(&challenge);
+        if root.ends_with(&custom) {
+            return root.to_path_buf();
+        }
+        root.join("signet").join(challenge)
+    }
+
     pub fn with_p2p_listen(mut self, addr: SocketAddr) -> Self {
         self.listen.p2p = P2pListen::Socket(addr);
         self
@@ -488,7 +514,7 @@ impl NodeConfig {
     }
 
     pub fn store_path(&self) -> PathBuf {
-        self.datadir.path().join("store")
+        self.datadir_path().join("store")
     }
 
     /// Cold store directory (`{datadir-cold}/store`) when `--datadir-cold` is set.
@@ -509,7 +535,7 @@ impl NodeConfig {
 
     /// Durable mempool directory (`{datadir}/mempool/`).
     pub fn mempool_path(&self) -> PathBuf {
-        self.datadir.path().join("mempool")
+        self.datadir_path().join("mempool")
     }
 
     pub fn milestone(&self) -> Milestone {
@@ -758,7 +784,7 @@ impl NodeConfig {
         self.rpc
             .token_file
             .clone()
-            .unwrap_or_else(|| rbitcoin_rpc::default_token_path(self.datadir.path()))
+            .unwrap_or_else(|| rbitcoin_rpc::default_token_path(&self.datadir_path()))
     }
 
     /// Configured Core cookie file for TCP HTTP Basic authentication.
@@ -771,7 +797,7 @@ impl NodeConfig {
         self.rpc
             .socket_path
             .clone()
-            .unwrap_or_else(|| rbitcoin_rpc::default_socket_path(self.datadir.path()))
+            .unwrap_or_else(|| rbitcoin_rpc::default_socket_path(&self.datadir_path()))
     }
 
     /// Owner-only mode for a directory this process just created.
@@ -796,14 +822,14 @@ impl NodeConfig {
     /// Create `{datadir}` and standard subdirs (`store`, `mempool`) if missing.
     pub fn ensure_datadir(&self) -> Result<(), NodeError> {
         self.validate()?;
-        let root = self.datadir.path();
+        let root = self.datadir_path();
         let created_root = !root.exists();
-        std::fs::create_dir_all(root).map_err(|source| NodeError::Datadir {
+        std::fs::create_dir_all(&root).map_err(|source| NodeError::Datadir {
             path: self.datadir.path.clone(),
             source,
         })?;
         if created_root {
-            Self::restrict_new_dir(root)?;
+            Self::restrict_new_dir(&root)?;
         }
         if root.exists() && !root.is_dir() {
             return Err(NodeError::Config(format!(
@@ -840,7 +866,7 @@ impl NodeConfig {
             }
         }
         if created_root {
-            rbitcoin_log::info!("node: created datadir {}", self.datadir.path().display());
+            rbitcoin_log::info!("node: created datadir {}", self.datadir_path().display());
         }
         Ok(())
     }
diff --git a/crates/rbitcoin-node/src/lock.rs b/crates/rbitcoin-node/src/lock.rs
index bef1a12f1..29a37d45d 100644
--- a/crates/rbitcoin-node/src/lock.rs
+++ b/crates/rbitcoin-node/src/lock.rs
@@ -23,7 +23,7 @@ pub fn lock_busy_msg(dir: &Path) -> String {
 /// Exclusive-lock the process datadir.
 pub fn lock_node_dirs(config: &NodeConfig) -> Result<DirLocks, NodeError> {
     Ok(DirLocks {
-        _files: vec![lock_dir(config.datadir.path())?],
+        _files: vec![lock_dir(&config.datadir_path())?],
     })
 }
 
diff --git a/crates/rbitcoin-node/src/run.rs b/crates/rbitcoin-node/src/run.rs
index 600d56454..add2e8cde 100644
--- a/crates/rbitcoin-node/src/run.rs
+++ b/crates/rbitcoin-node/src/run.rs
@@ -254,7 +254,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
         "rbitcoin-node starting version={} network={} datadir={}{} tip={start_tip} io={}",
         env!("CARGO_PKG_VERSION"),
         config.network.as_str(),
-        config.datadir.path().display(),
+        config.datadir_path().display(),
         config
             .datadir
             .cold
@@ -462,7 +462,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
             .expect("validate requires --tor-control with --listen-onion");
         let virt = config.network.default_p2p_port();
         let hs = ctl
-            .add_p2p_onion(config.datadir.path(), node.local_addr, virt)
+            .add_p2p_onion(&config.datadir_path(), node.local_addr, virt)
             .await?;
         info!("p2p onion {}.onion:{}", hs.service_id, virt);
         node.peers
@@ -473,7 +473,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
     }
     let mut i2p_sam = if let Some(addr) = config.listen.i2p_sam {
         let s = if config.listen.i2p_accept_incoming {
-            let dest = config.datadir.path().join("i2p").join("p2p.priv");
+            let dest = config.datadir_path().join("i2p").join("p2p.priv");
             rbitcoin_net::I2pSam::connect_persistent(addr, &dest).await
         } else {
             rbitcoin_net::I2pSam::connect(addr).await
@@ -516,7 +516,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
     } else {
         None
     };
-    let peers_path = config.datadir.path().join("peers");
+    let peers_path = config.datadir_path().join("peers");
     let mut addrman = match AddrMan::load(&peers_path) {
         Ok(am) => {
             if !am.is_empty() {
@@ -536,7 +536,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
             AddrMan::new()
         }
     };
-    let asmap = load_asmap(config.datadir.path(), config.asmap.as_deref());
+    let asmap = load_asmap(&config.datadir_path(), config.asmap.as_deref());
     addrman.set_asmap(asmap.clone());
     addrman.set_only_net(config.listen.only_net.clone());
     addrman.set_cjdns_reachable(config.listen.cjdns_reachable);
@@ -574,7 +574,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
         && !config.listen.has_pinned_connect()
         && addrman.is_empty()
     {
-        warn!("custom signet has no peers; use --connect ADDR or reuse a datadir with known peers");
+        info!("custom signet has no peers yet; keep listening or add --connect ADDR");
     }
     let shared_peers = std::sync::Arc::new(std::sync::Mutex::new(addrman.clone()));
     node.peers.set_addrman(std::sync::Arc::clone(&shared_peers));
@@ -808,7 +808,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
     .await;
     if let (Some(ctl), Some(h)) = (tor_ctl.as_mut(), electrum_handles.first()) {
         let hs = ctl
-            .add_electrum_onion(config.datadir.path(), h.local_addr)
+            .add_electrum_onion(&config.datadir_path(), h.local_addr)
             .await?;
         info!(
             "electrum onion {}.onion:{}",
@@ -832,7 +832,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
     if config.esplora_onion {
         if let (Some(ctl), Some(h)) = (tor_ctl.as_mut(), esplora_handles.first()) {
             let hs = ctl
-                .add_esplora_onion(config.datadir.path(), h.local_addr)
+                .add_esplora_onion(&config.datadir_path(), h.local_addr)
                 .await?;
             info!(
                 "esplora onion http://{}.onion:{} (/ws same port)",
@@ -851,7 +851,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
                 i2p_wallet.push(
                     start_i2p_named_forward(
                         addr,
-                        config.datadir.path(),
+                        &config.datadir_path(),
                         "electrum",
                         h.local_addr.port(),
                     )
@@ -862,7 +862,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
                 i2p_wallet.push(
                     start_i2p_named_forward(
                         addr,
-                        config.datadir.path(),
+                        &config.datadir_path(),
                         "esplora",
                         h.local_addr.port(),
                     )
@@ -938,7 +938,10 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
         }
     }
 
-    if tip_follow_ready && config.max_run_secs != Some(0) && !shutdown.requested() {
+    if (tip_follow_ready || config.network == Network::Signet)
+        && config.max_run_secs != Some(0)
+        && !shutdown.requested()
+    {
         let unbound = [
             (
                 "rpc",
@@ -1017,7 +1020,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
                     .await;
                     if let (Some(ctl), Some(h)) = (tor_ctl.as_mut(), handles.first()) {
                         let hs = ctl
-                            .add_electrum_onion(config.datadir.path(), h.local_addr)
+                            .add_electrum_onion(&config.datadir_path(), h.local_addr)
                             .await?;
                         info!(
                             "electrum onion {}.onion:{}",
@@ -1037,7 +1040,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
                                 i2p_wallet.push(
                                     start_i2p_named_forward(
                                         addr,
-                                        config.datadir.path(),
+                                        &config.datadir_path(),
                                         "electrum",
                                         h.local_addr.port(),
                                     )
@@ -1063,7 +1066,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
                     if config.esplora_onion {
                         if let (Some(ctl), Some(h)) = (tor_ctl.as_mut(), handles.first()) {
                             let hs = ctl
-                                .add_esplora_onion(config.datadir.path(), h.local_addr)
+                                .add_esplora_onion(&config.datadir_path(), h.local_addr)
                                 .await?;
                             info!(
                                 "esplora onion http://{}.onion:{} (/ws same port)",
@@ -1082,7 +1085,7 @@ pub async fn run_p2p(config: NodeConfig) -> Result<(), NodeError> {
                                 i2p_wallet.push(
                                     start_i2p_named_forward(
                                         addr,
-                                        config.datadir.path(),
+                                        &config.datadir_path(),
                                         "esplora",
                                         h.local_addr.port(),
                                     )
@@ -2253,6 +2256,7 @@ fn resolve_seednode(raw: &str, network: Network) -> Result<SocketAddr, String> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use bitcoin::hex::DisplayHex;
     use std::time::{SystemTime, UNIX_EPOCH};
     fn tiny_regtest(dir: impl AsRef<std::path::Path>) -> NodeConfig {
         NodeConfig::default()
@@ -2701,6 +2705,44 @@ mod tests {
         let _ = std::fs::remove_dir_all(&dir);
     }
 
+    #[test]
+    fn custom_signet_datadir_appends_challenge() {
+        let mut cfg = NodeConfig::default()
+            .with_datadir("/tmp/rbitcoin-custom-signet")
+            .with_network(rbitcoin_primitives::Network::Signet);
+        cfg.signet_challenge = Some(bitcoin::ScriptBuf::from_bytes(vec![0x51]));
+        assert_eq!(
+            cfg.datadir_path(),
+            std::path::Path::new("/tmp/rbitcoin-custom-signet/signet/51")
+        );
+
+        let already = NodeConfig::default()
+            .with_datadir("/tmp/rbitcoin-custom-signet/signet/51")
+            .with_network(rbitcoin_primitives::Network::Signet);
+        let mut already = already;
+        already.signet_challenge = Some(bitcoin::ScriptBuf::from_bytes(vec![0x51]));
+        assert_eq!(
+            already.datadir_path(),
+            std::path::Path::new("/tmp/rbitcoin-custom-signet/signet/51")
+        );
+    }
+
+    #[test]
+    fn default_signet_datadir_uses_builtin_challenge() {
+        let cfg = NodeConfig::default()
+            .with_datadir("/tmp/rbitcoin-default-signet")
+            .with_network(rbitcoin_primitives::Network::Signet);
+        let challenge = rbitcoin_consensus::ChainParams::signet()
+            .signet_challenge
+            .unwrap()
+            .as_bytes()
+            .to_lower_hex_string();
+        assert_eq!(
+            cfg.datadir_path(),
+            std::path::Path::new(&format!("/tmp/rbitcoin-default-signet/signet/{challenge}"))
+        );
+    }
+
     #[tokio::test]
     async fn cancelled_completes_after_request() {
         let sd = Shutdown::new();