diff --git a/Cargo.lock b/Cargo.lock
index db04bdca..2e3a4459 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -666,7 +666,7 @@ dependencies = [
  "libc",
  "log",
  "matches",
- "nix",
+ "nix 0.13.1",
  "serde",
  "thiserror",
  "wasm-bindgen",
@@ -834,7 +834,7 @@ dependencies = [
  "cfg-if 1.0.0",
  "crossbeam-utils",
  "lazy_static",
- "memoffset",
+ "memoffset 0.6.5",
  "scopeguard",
 ]
 
@@ -1414,6 +1414,7 @@ dependencies = [
  "hex",
  "hex-literal",
  "k256",
+ "nix 0.26.1",
  "once_cell",
  "open-fastrlp",
  "proc-macro2",
@@ -1424,6 +1425,7 @@ dependencies = [
  "serde_json",
  "strum",
  "syn",
+ "tempfile",
  "thiserror",
  "tiny-keccak",
  "unicode-xid",
@@ -2460,6 +2462,15 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "memoffset"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5de893c32cde5f383baa4c04c5d6dbdd735cfd4a794b0debdb2bb1b421da5ff4"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "memory_units"
 version = "0.4.0"
@@ -2530,6 +2541,20 @@ dependencies = [
  "void",
 ]
 
+[[package]]
+name = "nix"
+version = "0.26.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46a58d1d356c6597d08cde02c2f09d785b09e28711837b1ed667dc652c08a694"
+dependencies = [
+ "bitflags",
+ "cfg-if 1.0.0",
+ "libc",
+ "memoffset 0.7.1",
+ "pin-utils",
+ "static_assertions",
+]
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.46.0"
diff --git a/ethers-core/Cargo.toml b/ethers-core/Cargo.toml
index 987c1654..9dd1c927 100644
--- a/ethers-core/Cargo.toml
+++ b/ethers-core/Cargo.toml
@@ -44,6 +44,7 @@ syn = { version = "1.0.105", optional = true }
 proc-macro2 = { version = "1.0.47", optional = true }
 
 [dev-dependencies]
+tempfile = { version = "3.3.0", default-features = false }
 serde_json = { version = "1.0.64", default-features = false }
 bincode = { version = "1.3.3", default-features = false }
 once_cell = { version = "1.16.0" }
diff --git a/ethers-core/src/utils/geth.rs b/ethers-core/src/utils/geth.rs
index 04921c90..8657c888 100644
--- a/ethers-core/src/utils/geth.rs
+++ b/ethers-core/src/utils/geth.rs
@@ -331,15 +331,15 @@ impl Geth {
         }
 
         // Dev mode with custom block time
-        match self.mode {
+        let p2p_port = match self.mode {
             GethMode::Dev(DevOptions { block_time }) => {
                 cmd.arg("--dev");
                 if let Some(block_time) = block_time {
                     cmd.arg("--dev.period").arg(block_time.to_string());
                 }
+                None
             }
             GethMode::NonDev(PrivateNetOptions { p2p_port, discovery }) => {
-                // automatically enable and set the p2p port if we are in non-dev mode
                 let port = if let Some(port) = p2p_port { port } else { unused_port() };
                 cmd.arg("--port").arg(port.to_string());
 
@@ -347,8 +347,9 @@ impl Geth {
                 if !discovery {
                     cmd.arg("--nodiscover");
                 }
+                Some(port)
             }
-        }
+        };
 
         if let Some(chain_id) = self.chain_id {
             cmd.arg("--networkid").arg(chain_id.to_string());
@@ -400,11 +401,58 @@ impl Geth {
 
         child.stderr = Some(reader.into_inner());
 
-        let p2p_port = match self.mode {
-            GethMode::Dev(_) => None,
-            GethMode::NonDev(PrivateNetOptions { p2p_port, .. }) => p2p_port,
-        };
-
         GethInstance { pid: child, port, ipc: self.ipc_path, data_dir: self.data_dir, p2p_port }
     }
 }
+
+// These tests should use a different datadir for each `Geth` spawned
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn p2p_port() {
+        let temp_dir = tempfile::tempdir().unwrap();
+        let temp_dir_path = temp_dir.path().to_path_buf();
+
+        // disabling discovery should put the geth instance into non-dev mode, and it should have a
+        // p2p port.
+        let geth = Geth::new().disable_discovery().data_dir(temp_dir_path).spawn();
+        let p2p_port = geth.p2p_port();
+
+        drop(geth);
+        temp_dir.close().unwrap();
+
+        assert!(p2p_port.is_some());
+    }
+
+    #[test]
+    fn explicit_p2p_port() {
+        let temp_dir = tempfile::tempdir().unwrap();
+        let temp_dir_path = temp_dir.path().to_path_buf();
+
+        // if a p2p port is explicitly set, it should be used
+        let geth = Geth::new().p2p_port(1234).data_dir(temp_dir_path).spawn();
+        let p2p_port = geth.p2p_port();
+
+        drop(geth);
+        temp_dir.close().unwrap();
+
+        assert_eq!(p2p_port, Some(1234));
+    }
+
+    #[test]
+    fn dev_mode() {
+        let temp_dir = tempfile::tempdir().unwrap();
+        let temp_dir_path = temp_dir.path().to_path_buf();
+
+        // dev mode should not have a p2p port, and dev should be the default
+        let geth = Geth::new().data_dir(temp_dir_path).spawn();
+        let p2p_port = geth.p2p_port();
+
+        drop(geth);
+        temp_dir.close().unwrap();
+
+        assert!(p2p_port.is_none());
+    }
+}