diff --git a/src/chainspec/hl.rs b/src/chainspec/hl.rs
index 146e19d1f..a7dbb4f11 100644
--- a/src/chainspec/hl.rs
+++ b/src/chainspec/hl.rs
@@ -34,12 +34,10 @@ pub static HL_HARDFORKS: LazyLock<ChainHardforks> = LazyLock::new(|| {
     ])
 });
 
-/// The Hyperliqiud Mainnet spec
-pub fn hl_mainnet() -> ChainSpec {
+pub fn hl_chainspec(chain: Chain, genesis: &'static str) -> ChainSpec {
     ChainSpec {
-        chain: Chain::from_named(NamedChain::Hyperliquid),
-        genesis: serde_json::from_str(include_str!("genesis.json"))
-            .expect("Can't deserialize Hyperliquid Mainnet genesis json"),
+        chain,
+        genesis: serde_json::from_str(genesis).expect("Can't deserialize Hyperliquid genesis json"),
         genesis_header: empty_genesis_header(),
         paris_block_and_final_difficulty: Some((0, U256::from(0))),
         hardforks: HL_HARDFORKS.clone(),
@@ -48,6 +46,18 @@ pub fn hl_mainnet() -> ChainSpec {
     }
 }
 
+/// The Hyperliqiud Mainnet spec
+pub fn hl_mainnet() -> ChainSpec {
+    hl_chainspec(Chain::from_named(NamedChain::Hyperliquid), include_str!("genesis.json"))
+}
+
+/// The Hyperliqiud Testnet spec
+pub fn hl_testnet() -> ChainSpec {
+    // Note: Testnet sync starts from snapshotted state [1] instead of genesis block.
+    // So the `alloc` field is not used, which makes it fine to reuse mainnet genesis file.
+    hl_chainspec(Chain::from_id_unchecked(998), include_str!("genesis.json"))
+}
+
 /// Empty genesis header for Hyperliquid Mainnet.
 ///
 /// The exact value is not known per se, but the parent hash of block 1 is known to be
diff --git a/src/chainspec/parser.rs b/src/chainspec/parser.rs
index d7fa4fcc8..610e5f212 100644
--- a/src/chainspec/parser.rs
+++ b/src/chainspec/parser.rs
@@ -1,11 +1,11 @@
-use crate::chainspec::HlChainSpec;
+use crate::chainspec::{hl::hl_testnet, HlChainSpec};
 
 use super::hl::hl_mainnet;
 use reth_cli::chainspec::ChainSpecParser;
 use std::sync::Arc;
 
 /// Chains supported by HyperEVM. First value should be used as the default.
-pub const SUPPORTED_CHAINS: &[&str] = &["mainnet"];
+pub const SUPPORTED_CHAINS: &[&str] = &["mainnet", "testnet"];
 
 /// Hyperliquid chain specification parser.
 #[derive(Debug, Clone, Default)]
@@ -27,6 +27,7 @@ impl ChainSpecParser for HlChainSpecParser {
 pub fn chain_value_parser(s: &str) -> eyre::Result<Arc<HlChainSpec>> {
     match s {
         "mainnet" => Ok(Arc::new(HlChainSpec { inner: hl_mainnet() })),
+        "testnet" => Ok(Arc::new(HlChainSpec { inner: hl_testnet() })),
         _ => Err(eyre::eyre!("Unsupported chain: {}", s)),
     }
 }
diff --git a/src/pseudo_peer/mod.rs b/src/pseudo_peer/mod.rs
index 991508b11..9dba0f3e5 100644
--- a/src/pseudo_peer/mod.rs
+++ b/src/pseudo_peer/mod.rs
@@ -50,6 +50,7 @@ pub async fn start_pseudo_peer(
 
     // Create network manager
     let (mut network, start_tx) = create_network_manager::<BlockSourceBoxed>(
+        (*chain_spec).clone(),
         destination_peer,
         block_source.clone(),
         blockhash_cache.clone(),
diff --git a/src/pseudo_peer/network.rs b/src/pseudo_peer/network.rs
index 98e0efdf1..dda503353 100644
--- a/src/pseudo_peer/network.rs
+++ b/src/pseudo_peer/network.rs
@@ -19,6 +19,7 @@ pub struct NetworkBuilder {
     boot_nodes: Vec<TrustedPeer>,
     discovery_port: u16,
     listener_port: u16,
+    chain_spec: HlChainSpec,
 }
 
 impl Default for NetworkBuilder {
@@ -29,6 +30,7 @@ impl Default for NetworkBuilder {
             boot_nodes: vec![],
             discovery_port: 0,
             listener_port: 0,
+            chain_spec: HlChainSpec::default(),
         }
     }
 }
@@ -55,6 +57,11 @@ impl NetworkBuilder {
         self
     }
 
+    pub fn with_chain_spec(mut self, chain_spec: HlChainSpec) -> Self {
+        self.chain_spec = chain_spec;
+        self
+    }
+
     pub async fn build<BS>(
         self,
         block_source: Arc<Box<dyn super::sources::BlockSource>>,
@@ -80,12 +87,14 @@ impl NetworkBuilder {
 }
 
 pub async fn create_network_manager<BS>(
+    chain_spec: HlChainSpec,
     destination_peer: String,
     block_source: Arc<Box<dyn super::sources::BlockSource>>,
     blockhash_cache: BlockHashCache,
 ) -> eyre::Result<(NetworkManager<HlNetworkPrimitives>, mpsc::Sender<()>)> {
     NetworkBuilder::default()
         .with_boot_nodes(vec![TrustedPeer::from_str(&destination_peer).unwrap()])
+        .with_chain_spec(chain_spec)
         .build::<BS>(block_source, blockhash_cache)
         .await
 }