diff --git a/core/server/api/canary/utils/serializers/input/tiers.js b/core/server/api/canary/utils/serializers/input/tiers.js
index 603ff770cb..2572829ff1 100644
--- a/core/server/api/canary/utils/serializers/input/tiers.js
+++ b/core/server/api/canary/utils/serializers/input/tiers.js
@@ -45,10 +45,26 @@ function convertTierInput(input) {
 
 module.exports = {
     all(_apiConfig, frame) {
+        if (localUtils.isContentAPI(frame)) {
+            // CASE: content api can only have active tiers
+            forceActiveFilter(frame);
+
+            // CASE: content api includes these by default
+            const defaultRelations = ['monthly_price', 'yearly_price', 'benefits'];
+            if (!frame.options.withRelated) {
+                frame.options.withRelated = defaultRelations;
+            } else {
+                for (const relation of defaultRelations) {
+                    if (!frame.options.withRelated.includes(relation)) {
+                        frame.options.withRelated.push(relation);
+                    }
+                }
+            }
+        }
+
         if (!frame.options.withRelated) {
             return;
         }
-
         frame.options.withRelated = frame.options.withRelated.map((relation) => {
             if (relation === 'stripe_prices') {
                 return 'stripePrices';
@@ -63,13 +79,6 @@ module.exports = {
         });
     },
 
-    browse(_apiConfig, frame) {
-        if (localUtils.isContentAPI(frame)) {
-            // CASE: content api can only has active tiers
-            forceActiveFilter(frame);
-        }
-    },
-
     add(_apiConfig, frame) {
         if (frame.data.products) {
             frame.data = convertTierInput(frame.data.products[0]);
diff --git a/core/server/api/canary/utils/serializers/output/tiers.js b/core/server/api/canary/utils/serializers/output/tiers.js
index 2bd3220ab1..87116d5176 100644
--- a/core/server/api/canary/utils/serializers/output/tiers.js
+++ b/core/server/api/canary/utils/serializers/output/tiers.js
@@ -2,6 +2,7 @@
 const debug = require('@tryghost/debug')('api:canary:utils:serializers:output:tiers');
 
 const allowedIncludes = ['monthly_price', 'yearly_price'];
+const localUtils = require('../../index');
 const utils = require('../../../../shared/utils');
 
 module.exports = {
@@ -21,15 +22,9 @@ module.exports = {
  * @returns {{tiers: SerializedTier[], meta: PageMeta}}
  */
 function paginatedTiers(page, _apiConfig, frame) {
-    const requestedQueryIncludes = frame.original && frame.original.query && frame.original.query.include && frame.original.query.include.split(',') || [];
-    const requestedOptionsIncludes = utils.options.trimAndLowerCase(frame.original && frame.original.options && frame.original.options.include || []);
     return {
         tiers: page.data.map((model) => {
-            return cleanIncludes(
-                allowedIncludes,
-                requestedQueryIncludes.concat(requestedOptionsIncludes),
-                serializeTier(model, frame.options, frame.apiType)
-            );
+            return serializeTier(model, frame.options, frame);
         }),
         meta: page.meta
     };
@@ -43,15 +38,9 @@ function paginatedTiers(page, _apiConfig, frame) {
  * @returns {{tiers: SerializedTier[]}}
  */
 function singleTier(model, _apiConfig, frame) {
-    const requestedQueryIncludes = frame.original && frame.original.query && frame.original.query.include && frame.original.query.include.split(',') || [];
-    const requestedOptionsIncludes = frame.original && frame.original.options && frame.original.options.include || [];
     return {
         tiers: [
-            cleanIncludes(
-                allowedIncludes,
-                requestedQueryIncludes.concat(requestedOptionsIncludes),
-                serializeTier(model, frame.options, frame.apiType)
-            )
+            serializeTier(model, frame.options, frame)
         ]
     };
 }
@@ -59,10 +48,11 @@ function singleTier(model, _apiConfig, frame) {
 /**
  * @param {import('bookshelf').Model} tier
  * @param {object} options
+ * @param {object} frame
  *
  * @returns {SerializedTier}
  */
-function serializeTier(tier, options) {
+function serializeTier(tier, options, frame) {
     const json = tier.toJSON(options);
 
     const serialized = {
@@ -91,6 +81,17 @@ function serializeTier(tier, options) {
         serialized.yearly_price = json.yearlyPrice?.amount;
     }
 
+    if (!localUtils.isContentAPI(frame)) {
+        const requestedQueryIncludes = frame.original && frame.original.query && frame.original.query.include && frame.original.query.include.split(',') || [];
+        const requestedOptionsIncludes = utils.options.trimAndLowerCase(frame.original && frame.original.options && frame.original.options.include || []);
+
+        return cleanIncludes(
+            allowedIncludes,
+            requestedQueryIncludes.concat(requestedOptionsIncludes),
+            serialized
+        );
+    }
+
     return serialized;
 }
 
diff --git a/test/e2e-api/content/tiers.test.js b/test/e2e-api/content/tiers.test.js
index 3972079794..1d31ae1dce 100644
--- a/test/e2e-api/content/tiers.test.js
+++ b/test/e2e-api/content/tiers.test.js
@@ -10,7 +10,7 @@ describe('Tiers Content API', function () {
     });
 
     it('Can request only active tiers', async function () {
-        await agent.get('/tiers/?include=monthly_price,yearly_price,benefits')
+        await agent.get('/tiers/?include=monthly_price')
             .expectStatus(200)
             .matchHeaderSnapshot({
                 etag: matchers.anyEtag