diff --git a/packages/entity/index.js b/packages/entity/index.js
index a437c1f..ac7b296 100644
--- a/packages/entity/index.js
+++ b/packages/entity/index.js
@@ -119,6 +119,7 @@ export class Entity extends decorate(Resource) {
   constructor(json, jsonext) {
     super();
     this._hooks = {};
+    this._hydrationPromise = undefined;
     this._json = Entity.jsonWithDefaults(json);
     this._traits = {};
     this._traitsFlat = [];
@@ -230,11 +231,14 @@ export class Entity extends decorate(Resource) {
   }
 
   hydrate() {
-    const promises = [];
-    for (let i = 0; i < this._traitsFlat.length; i++) {
-      promises.push(this._traitsFlat[i].hydrate());
+    if (!this._hydrationPromise) {
+      const promises = [];
+      for (let i = 0; i < this._traitsFlat.length; i++) {
+        promises.push(this._traitsFlat[i].hydrate());
+      }
+      this._hydrationPromise = Promise.all(promises);
     }
-    return Promise.all(promises);
+    return this._hydrationPromise;
   }
 
   invokeHook(hook, ...args) {