diff --git a/fendermint/testing/materializer/src/docker/node.rs b/fendermint/testing/materializer/src/docker/node.rs
index 3bfbc94be..1863171cd 100644
--- a/fendermint/testing/materializer/src/docker/node.rs
+++ b/fendermint/testing/materializer/src/docker/node.rs
@@ -5,6 +5,7 @@ use std::{
     collections::BTreeMap,
     os::unix::fs::MetadataExt,
     path::{Path, PathBuf},
+    str::FromStr,
 };
 
 use anyhow::{anyhow, bail, Context};
@@ -21,7 +22,7 @@ use crate::{
     env_vars,
     materializer::{NodeConfig, TargetConfig},
     materials::export_file,
-    HasEthApi, NodeName, ResourceHash,
+    HasCometBftApi, HasEthApi, NodeName, ResourceHash,
 };
 
 // TODO: Add these to the materializer.
@@ -475,6 +476,16 @@ impl HasEthApi for DockerNode {
     }
 }
 
+impl HasCometBftApi for DockerNode {
+    fn cometbft_http_endpoint(&self) -> tendermint_rpc::Url {
+        tendermint_rpc::Url::from_str(&format!(
+            "http://127.0.0.1:{}",
+            self.port_range.cometbft_rpc_host_port()
+        ))
+        .unwrap()
+    }
+}
+
 /// Create a container name from a node name and a logical container name, e.g. "cometbft"
 /// in a way that we can use it as a hostname without being too long.
 ///
diff --git a/fendermint/testing/materializer/src/lib.rs b/fendermint/testing/materializer/src/lib.rs
index 021425810..ccddc91ae 100644
--- a/fendermint/testing/materializer/src/lib.rs
+++ b/fendermint/testing/materializer/src/lib.rs
@@ -323,6 +323,17 @@ pub trait HasEthApi {
     }
 }
 
+pub trait HasCometBftApi {
+    /// URL of the HTTP endpoint.
+    fn cometbft_http_endpoint(&self) -> tendermint_rpc::Url;
+
+    fn cometbft_http_provider(&self) -> anyhow::Result<tendermint_rpc::HttpClient> {
+        Ok(tendermint_rpc::HttpClient::new(
+            self.cometbft_http_endpoint(),
+        )?)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::path::PathBuf;
diff --git a/fendermint/testing/materializer/tests/docker.rs b/fendermint/testing/materializer/tests/docker.rs
index 17a8aa89e..60b1a1504 100644
--- a/fendermint/testing/materializer/tests/docker.rs
+++ b/fendermint/testing/materializer/tests/docker.rs
@@ -6,23 +6,33 @@
 //!
 //! `cargo test -p fendermint_materializer --test docker -- --nocapture`
 
-use std::{env::current_dir, path::PathBuf, pin::Pin, time::Duration};
+use std::{
+    collections::BTreeSet,
+    env::current_dir,
+    path::PathBuf,
+    pin::Pin,
+    time::{Duration, Instant},
+};
 
-use anyhow::Context;
+use anyhow::{anyhow, Context};
+use ethers::providers::Middleware;
 use fendermint_materializer::{
     docker::{DockerMaterializer, DockerMaterials},
     manifest::Manifest,
     testnet::Testnet,
     validation::validate_manifest,
-    TestnetName,
+    HasCometBftApi, HasEthApi, TestnetName,
 };
 use futures::Future;
 use lazy_static::lazy_static;
+use tendermint_rpc::Client;
+
+pub type DockerTestnet = Testnet<DockerMaterials, DockerMaterializer>;
 
 lazy_static! {
     static ref CI_PROFILE: bool = std::env::var("PROFILE").unwrap_or_default() == "ci";
-    static ref STARTUP_WAIT_SECS: u64 = if *CI_PROFILE { 20 } else { 15 };
-    static ref TEARDOWN_WAIT_SECS: u64 = 5;
+    static ref STARTUP_TIMEOUT: Duration = Duration::from_secs(60);
+    static ref TEARDOWN_TIMEOUT: Duration = Duration::from_secs(5);
     static ref PRINT_LOGS_ON_ERROR: bool = *CI_PROFILE;
 }
 
@@ -62,7 +72,7 @@ where
     F: for<'a> FnOnce(
         &Manifest,
         &mut DockerMaterializer,
-        &'a mut Testnet<DockerMaterials, DockerMaterializer>,
+        &'a mut DockerTestnet,
     ) -> Pin<Box<dyn Future<Output = anyhow::Result<()>> + 'a>>,
 {
     let testnet_name = TestnetName::new(
@@ -92,10 +102,13 @@ where
         .await
         .context("failed to set up testnet")?;
 
-    // Allow time for things to consolidate and blocks to be created.
-    tokio::time::sleep(Duration::from_secs(*STARTUP_WAIT_SECS)).await;
+    let started = wait_for_startup(&testnet).await?;
 
-    let res = f(&manifest, &mut materializer, &mut testnet).await;
+    let res = if started {
+        f(&manifest, &mut materializer, &mut testnet).await
+    } else {
+        Err(anyhow!("the startup sequence timed out"))
+    };
 
     // Print all logs on failure.
     // Some might be available in logs in the files which are left behind,
@@ -123,11 +136,47 @@ where
     // otherwise the system shuts down too quick, but
     // at least we can inspect the containers.
     // If they don't all get dropped, `docker system prune` helps.
-    tokio::time::sleep(Duration::from_secs(*TEARDOWN_WAIT_SECS)).await;
+    tokio::time::sleep(*TEARDOWN_TIMEOUT).await;
 
     res
 }
 
+/// Allow time for things to consolidate and APIs to start.
+async fn wait_for_startup(testnet: &DockerTestnet) -> anyhow::Result<bool> {
+    let start = Instant::now();
+    let mut started = BTreeSet::new();
+
+    'startup: loop {
+        if start.elapsed() > *STARTUP_TIMEOUT {
+            return Ok(false);
+        }
+        tokio::time::sleep(Duration::from_secs(5)).await;
+
+        for (name, dnode) in testnet.nodes() {
+            if started.contains(name) {
+                continue;
+            }
+
+            let client = dnode.cometbft_http_provider()?;
+
+            if client.abci_info().await.is_err() {
+                continue 'startup;
+            }
+
+            if let Some(client) = dnode.ethapi_http_provider()? {
+                if client.get_chainid().await.is_err() {
+                    continue 'startup;
+                }
+            }
+
+            started.insert(name.clone());
+        }
+
+        // All of them succeeded.
+        return Ok(true);
+    }
+}
+
 // Run these tests serially because they share a common `materializer-state.json` file with the port mappings.
 // Unfortunately the `#[serial]` macro can only be applied to module blocks, not this.
 mod docker_tests;