diff --git a/integration_tests/tests/cross_zone_watcher_restart.rs b/integration_tests/tests/cross_zone_watcher_restart.rs
new file mode 100644
index 00000000..155a29fc
--- /dev/null
+++ b/integration_tests/tests/cross_zone_watcher_restart.rs
@@ -0,0 +1,227 @@
+#![expect(
+    clippy::tests_outside_test_module,
+    reason = "top-level test functions are conventional for integration tests"
+)]
+
+//! A sequencer restart must resume its cross-zone watcher from the persisted
+//! per-peer delivery floor instead of re-reading the peer channel from genesis.
+//!
+//! Re-reading is safe (the dispatch key is content-addressed and the inbox
+//! no-ops a replay) so on-chain state cannot tell the two apart. What does tell
+//! them apart is the transactions: a watcher that lost its cursor re-injects
+//! every already-delivered dispatch, which shows up as inbox transactions in
+//! blocks produced after the restart. This is the only test that covers the
+//! wiring from `spawn_watchers` through the store, so a silent regression here
+//! would leave every other test green while the feature does nothing.
+
+use std::time::Duration;
+
+use anyhow::{Context as _, Result};
+use common::transaction::LeeTransaction;
+use cross_zone_outbox_core::outbox_pda;
+use integration_tests::{
+    config::{self, SequencerPartialConfig},
+    setup::{SequencerSetup, sequencer_client, setup_bedrock_node},
+};
+use lee::{AccountId, PublicTransaction, public_transaction::Message};
+use lee_core::program::ProgramId;
+use ping_core::{ReceiverInstruction, SenderInstruction, ping_record_pda};
+use sequencer_core::config::{CrossZoneConfig, CrossZonePeer};
+use sequencer_service_rpc::{RpcClient as _, SequencerClient};
+use tokio::test;
+
+const DELIVERY_TIMEOUT: Duration = Duration::from_secs(480);
+/// Blocks zone B must produce after the restart before we judge the watcher.
+/// A watcher that lost its cursor re-reads the peer channel on its first pass,
+/// so a handful of blocks is ample room for the replay to appear.
+const BLOCKS_AFTER_RESTART: u64 = 5;
+const RESTART_TIMEOUT: Duration = Duration::from_secs(240);
+const PING_PAYLOAD: &[u8] = b"hello-cross-zone";
+
+#[test]
+async fn restarted_watcher_resumes_instead_of_replaying_the_peer_channel() -> Result<()> {
+    // Declared first so it outlives both zones (drops run in reverse order).
+    let (_bedrock, bedrock_addr) = setup_bedrock_node()
+        .await
+        .context("Failed to set up shared Bedrock node")?;
+
+    let partial = SequencerPartialConfig::default();
+    let channel_a = config::bedrock_channel_id();
+    let channel_b = config::bedrock_channel_id_b();
+    let zone_a: [u8; 32] = *channel_a.as_ref();
+    let zone_b: [u8; 32] = *channel_b.as_ref();
+    let receiver_id = programs::ping_receiver().id();
+
+    let cross_zone = CrossZoneConfig {
+        peers: vec![CrossZonePeer {
+            channel_id: zone_a,
+            allowed_targets: vec![receiver_id],
+            expected_block_signing_pubkey: None,
+        }],
+    };
+
+    let (seq_a, _seq_a_home) = SequencerSetup::new(partial, bedrock_addr)
+        .with_channel_id(channel_a)
+        .with_genesis(vec![])
+        .setup()
+        .await
+        .context("Failed to set up zone A sequencer")?;
+
+    // Zone B keeps an explicit home so it can be restarted on the same store.
+    let home_b = tempfile::tempdir().context("Failed to create zone B home")?;
+    let mut seq_b = SequencerSetup::new(partial, bedrock_addr)
+        .with_channel_id(channel_b)
+        .with_genesis(vec![])
+        .with_cross_zone(cross_zone.clone())
+        .setup_at(home_b.path())
+        .await
+        .context("Failed to set up zone B sequencer")?;
+
+    // Deliver one ping, so the peer channel holds a dispatch worth replaying.
+    sequencer_client(seq_a.addr())?
+        .send_transaction(build_ping_tx(zone_b, receiver_id))
+        .await
+        .context("Failed to submit ping on zone A")?;
+    let record_id = ping_record_pda(receiver_id);
+    let delivered = wait_for_delivery(sequencer_client(seq_b.addr())?, record_id).await?;
+    assert_eq!(
+        delivered, PING_PAYLOAD,
+        "Zone B must record the payload before the restart"
+    );
+
+    let tip_before = sequencer_client(seq_b.addr())?.get_last_block_id().await?;
+
+    // Restart zone B on the same home. Zone A stays quiet from here, so any
+    // inbox transaction after the restart is a replay, not a new delivery.
+    //
+    // `shutdown` rather than `drop`: dropping aborts the main loop without
+    // awaiting it and leaves the watchers and the publisher's drive task holding
+    // the store, so the reopen below would race the `RocksDB` lock.
+    seq_b.shutdown().await;
+    seq_b = SequencerSetup::new(partial, bedrock_addr)
+        .with_channel_id(channel_b)
+        .with_genesis(vec![])
+        .with_cross_zone(cross_zone)
+        .setup_at(home_b.path())
+        .await
+        .context("Failed to restart zone B sequencer")?;
+    let client_b = sequencer_client(seq_b.addr())?;
+
+    let tip_after = wait_for_block_id(
+        &client_b,
+        tip_before.saturating_add(BLOCKS_AFTER_RESTART),
+        RESTART_TIMEOUT,
+    )
+    .await?;
+
+    let replayed = count_inbox_transactions(&client_b, tip_before.saturating_add(1), tip_after)
+        .await
+        .context("Failed to scan zone B blocks after the restart")?;
+    assert_eq!(
+        replayed,
+        0,
+        "a restarted watcher must resume from its persisted delivery floor; found {replayed} inbox transaction(s) in blocks {}..={tip_after}, which means it re-read the peer channel from genesis",
+        tip_before.saturating_add(1)
+    );
+
+    // The delivery itself must survive the restart untouched.
+    let account = client_b.get_account(record_id).await?;
+    assert_eq!(
+        account.data.into_inner(),
+        PING_PAYLOAD,
+        "the delivered payload must survive the restart"
+    );
+    Ok(())
+}
+
+/// Counts inbox transactions across `from..=to`, the signature of a re-injected
+/// dispatch.
+async fn count_inbox_transactions(client: &SequencerClient, from: u64, to: u64) -> Result<usize> {
+    let inbox_id = programs::cross_zone_inbox().id();
+    let mut count = 0_usize;
+    for block_id in from..=to {
+        let Some(block) = client.get_block(block_id).await? else {
+            continue;
+        };
+        for tx in &block.body.transactions {
+            if let LeeTransaction::Public(public_tx) = tx
+                && public_tx.message().program_id == inbox_id
+            {
+                count = count.saturating_add(1);
+            }
+        }
+    }
+    Ok(count)
+}
+
+/// Waits until the sequencer's tip reaches `target`, returning the tip.
+async fn wait_for_block_id(
+    client: &SequencerClient,
+    target: u64,
+    timeout: Duration,
+) -> Result<u64> {
+    let wait = async {
+        loop {
+            let tip = client.get_last_block_id().await?;
+            if tip >= target {
+                return Ok::<u64, anyhow::Error>(tip);
+            }
+            tokio::time::sleep(Duration::from_secs(2)).await;
+        }
+    };
+    tokio::time::timeout(timeout, wait)
+        .await
+        .context("Zone B did not produce enough blocks after the restart")?
+}
+
+/// Builds a top-level `ping_sender` transaction that chains into the outbox to emit
+/// a message carrying a `ping_receiver::Record` instruction for the target zone.
+fn build_ping_tx(target_zone: [u8; 32], receiver_id: ProgramId) -> LeeTransaction {
+    let outbox_id = programs::cross_zone_outbox().id();
+    let ordinal = 0;
+
+    let words = risc0_zkvm::serde::to_vec(&ReceiverInstruction::Record {
+        payload: PING_PAYLOAD.to_vec(),
+    })
+    .expect("serialize ping instruction");
+    let payload: Vec<u8> = words.iter().flat_map(|word| word.to_le_bytes()).collect();
+
+    let send = SenderInstruction::Send {
+        outbox_program_id: outbox_id,
+        target_zone,
+        target_program_id: receiver_id,
+        target_accounts: vec![ping_record_pda(receiver_id).into_value()],
+        payload,
+        ordinal,
+    };
+
+    let outbox_account = outbox_pda(outbox_id, &target_zone, ordinal);
+    let message = Message::try_new(
+        programs::ping_sender().id(),
+        vec![outbox_account],
+        vec![],
+        send,
+    )
+    .expect("build ping message");
+    LeeTransaction::Public(PublicTransaction::new(
+        message,
+        lee::public_transaction::WitnessSet::from_raw_parts(vec![]),
+    ))
+}
+
+/// Polls zone B's sequencer until the ping record PDA holds a payload.
+async fn wait_for_delivery(client: SequencerClient, record_id: AccountId) -> Result<Vec<u8>> {
+    let wait = async {
+        loop {
+            let account = client.get_account(record_id).await?;
+            let data = account.data.into_inner();
+            if !data.is_empty() {
+                return Ok::<Vec<u8>, anyhow::Error>(data);
+            }
+            tokio::time::sleep(Duration::from_secs(3)).await;
+        }
+    };
+    tokio::time::timeout(DELIVERY_TIMEOUT, wait)
+        .await
+        .context("Zone B did not record the cross-zone payload in time")?
+}