diff --git a/end-to-end-tests/src/instance_launch.rs b/end-to-end-tests/src/instance_launch.rs
index 306d697f5d4..648d49e4d6f 100644
--- a/end-to-end-tests/src/instance_launch.rs
+++ b/end-to-end-tests/src/instance_launch.rs
@@ -95,7 +95,7 @@ async fn instance_launch() -> Result<()> {
         .context("no external IPs")?
         .clone();
 
-    let ExternalIp::Ephemeral { ip: ip_addr } = ip_addr else {
+    let ExternalIp::Ephemeral { ip: ip_addr, .. } = ip_addr else {
         anyhow::bail!("IP bound to instance was not ephemeral as required.")
     };
     eprintln!("instance external IP: {}", ip_addr);
diff --git a/nexus/db-model/src/external_ip.rs b/nexus/db-model/src/external_ip.rs
index fce8d21a3c3..7e4ef9f7f5b 100644
--- a/nexus/db-model/src/external_ip.rs
+++ b/nexus/db-model/src/external_ip.rs
@@ -529,9 +529,10 @@ impl TryFrom<ExternalIp> for views::ExternalIp {
         }
         match ip.kind {
             IpKind::Floating => Ok(views::ExternalIp::Floating(ip.try_into()?)),
-            IpKind::Ephemeral => {
-                Ok(views::ExternalIp::Ephemeral { ip: ip.ip.ip() })
-            }
+            IpKind::Ephemeral => Ok(views::ExternalIp::Ephemeral {
+                ip: ip.ip.ip(),
+                ip_pool_id: ip.ip_pool_id,
+            }),
             IpKind::SNat => Err(Error::internal_error(
                 "SNAT IP addresses should not be exposed in the API",
             )),
diff --git a/nexus/types/src/external_api/views.rs b/nexus/types/src/external_api/views.rs
index 88c1d177ddb..16bb37b24af 100644
--- a/nexus/types/src/external_api/views.rs
+++ b/nexus/types/src/external_api/views.rs
@@ -501,14 +501,14 @@ pub struct IpPoolRange {
 #[derive(Debug, Clone, Deserialize, PartialEq, Serialize, JsonSchema)]
 #[serde(tag = "kind", rename_all = "snake_case")]
 pub enum ExternalIp {
-    Ephemeral { ip: IpAddr },
+    Ephemeral { ip: IpAddr, ip_pool_id: Uuid },
     Floating(FloatingIp),
 }
 
 impl ExternalIp {
     pub fn ip(&self) -> IpAddr {
         match self {
-            Self::Ephemeral { ip } => *ip,
+            Self::Ephemeral { ip, .. } => *ip,
             Self::Floating(float) => float.ip,
         }
     }
diff --git a/openapi/nexus.json b/openapi/nexus.json
index 216744207d5..0edec31234b 100644
--- a/openapi/nexus.json
+++ b/openapi/nexus.json
@@ -17507,6 +17507,10 @@
                 "type": "string",
                 "format": "ip"
               },
+              "ip_pool_id": {
+                "type": "string",
+                "format": "uuid"
+              },
               "kind": {
                 "type": "string",
                 "enum": [
@@ -17516,6 +17520,7 @@
             },
             "required": [
               "ip",
+              "ip_pool_id",
               "kind"
             ]
           },