diff --git a/closure/goog/labs/useragent/browser.js b/closure/goog/labs/useragent/browser.js
index aa3fe5f031..2831f8562a 100644
--- a/closure/goog/labs/useragent/browser.js
+++ b/closure/goog/labs/useragent/browser.js
@@ -19,7 +19,7 @@ const googAsserts = goog.require('goog.asserts');
 const util = goog.require('goog.labs.userAgent.util');
 const {AsyncValue, Version} = goog.require('goog.labs.userAgent.highEntropy.highEntropyValue');
 const {compareVersions} = goog.require('goog.string.internal');
-const {fullVersionList} = goog.require('goog.labs.userAgent.highEntropy.highEntropyData');
+const {fullVersionList, hasFullVersionList} = goog.require('goog.labs.userAgent.highEntropy.highEntropyData');
 
 // TODO(nnaze): Refactor to remove excessive exclusion logic in matching
 // functions.
@@ -624,6 +624,23 @@ class UserAgentStringFallbackBrandVersion {
   }
 }
 
+/**
+ * Requests all full browser versions to be cached.  When the returned promise
+ * resolves, subsequent calls to `fullVersionOf(...).getIfLoaded()` will return
+ * a value.
+ *
+ * This method should be avoided in favor of directly awaiting
+ * `fullVersionOf(...).load()` where it is used.
+ *
+ * @return {!Promise<void>}
+ */
+async function loadFullVersions() {
+  if (useUserAgentBrand() && hasFullVersionList()) {
+    await fullVersionList.load();
+  }
+}
+exports.loadFullVersions = loadFullVersions;
+
 /**
  * Returns an object that provides access to the full version string of the
  * current browser -- or undefined, based on whether the current browser matches
@@ -636,15 +653,9 @@ class UserAgentStringFallbackBrandVersion {
  * undefined if the current browser doesn't match the given brand.
  */
 function fullVersionOf(browser) {
-  // fullVersionList is currently not implemented in Chromium. Therefore, don't
-  // check fullVersionList until Chromium 101. We choose 101 as a reasonable
-  // upper bound for when fullVersionList is estimated to have been implemented.
-  // TODO(user): If fullVersionList is implemented in an earlier version
-  // of Chromium, lower this value to compare against that major version.
-  // Additionally, Silk currently does not identify itself in its
-  // userAgentData.brands array, so if checking its version, always fall back to
-  // the user agent string.
-  if (useUserAgentBrand() && !(versionOf(Brand.CHROMIUM) < 101)) {
+  // Silk currently does not identify itself in its userAgentData.brands array,
+  // so if checking its version, always fall back to the user agent string.
+  if (useUserAgentBrand() && hasFullVersionList()) {
     const data = util.getUserAgentData();
     // Operate under the assumption that the low-entropy and high-entropy lists
     // of brand/version pairs contain an identical set of brands. Therefore, if
diff --git a/closure/goog/labs/useragent/browser_test.js b/closure/goog/labs/useragent/browser_test.js
index fa3000adc4..6fd8fae7e5 100644
--- a/closure/goog/labs/useragent/browser_test.js
+++ b/closure/goog/labs/useragent/browser_test.js
@@ -273,6 +273,7 @@ testSuite({
     util.setUserAgent('');
     util.setUserAgentData(null);
     highEntropyData.resetAllForTesting();
+    highEntropyData.setHasFullVersionListForTesting(false);
   },
 
   async testOpera10() {
@@ -947,6 +948,7 @@ testSuite({
           ]
         });
     util.setUserAgentData(userAgentDataWithVersion);
+    highEntropyData.setHasFullVersionListForTesting(true);
 
     assertBrowser(Browser.CHROME);
     assertNonChromeChromiumBrowser(NonChromeChromiumBrowser.OPERA_CHROMIUM);
@@ -984,6 +986,7 @@ testSuite({
           ]
         });
     util.setUserAgentData(userAgentDataWithVersion);
+    highEntropyData.setHasFullVersionListForTesting(true);
 
     assertBrowser(Browser.CHROME);
     assertNonChromeChromiumBrowser(NonChromeChromiumBrowser.EDGE_CHROMIUM);
@@ -1055,6 +1058,7 @@ testSuite({
         testAgentData.CHROME_USERAGENT_DATA,
         {fullVersionList: [{brand: 'Chromium', version: '101.0.4472.77'}]});
     util.setUserAgentData(userAgentDataWithVersion);
+    highEntropyData.setHasFullVersionListForTesting(true);
 
     assertBrowser(Browser.CHROME);
     assertTrue(userAgentBrowser.isChrome());
@@ -1105,6 +1109,7 @@ testSuite({
 
   async testChromeUserAgentDataWithRejectedHighEntropyValues() {
     util.setUserAgentData(testAgentData.CHROME_USERAGENT_DATA);
+    highEntropyData.setHasFullVersionListForTesting(true);
 
     const fullChromeVersion =
         userAgentBrowser.fullVersionOf(userAgentBrowser.Brand.CHROMIUM);
@@ -1118,4 +1123,45 @@ testSuite({
         userAgentBrowser.Brand.CHROMIUM, '101', '101');
     await assertGetVersionStringForLogging(DEFINITELY_NOT_A_BROWSER, '', '');
   },
+
+  async testChromeUserAgentDataPreloadedFullVersion() {
+    // Note: The full versions listed here are fictional, made up by bumping
+    // a legitimate version's major version number by 10 (e.g. 91.* -> 101.*).
+    const userAgentDataWithVersion = testAgentData.withHighEntropyData(
+        testAgentData.CHROME_USERAGENT_DATA,
+        {fullVersionList: [{brand: 'Chromium', version: '101.0.4472.77'}]});
+    util.setUserAgentData(userAgentDataWithVersion);
+    highEntropyData.setHasFullVersionListForTesting(true);
+
+    const fullChromeVersion =
+        userAgentBrowser.fullVersionOf(userAgentBrowser.Brand.CHROMIUM);
+    assertNotNullNorUndefined(fullChromeVersion);
+    assertEquals(undefined, fullChromeVersion.getIfLoaded());
+
+    // Preload the full version list.
+    await userAgentBrowser.loadFullVersions();
+    assertEquals(
+        '101.0.4472.77',
+        fullChromeVersion.getIfLoaded().toVersionStringForLogging());
+  },
+
+  async testChromeNoFullVersionUserAgentDataPreloadedFullVersion() {
+    util.setUserAgent(testAgents.CHROME_LINUX_91);
+    util.setUserAgentData(
+        testAgentData.CHROME_NO_FULLVERSIONLIST_USERAGENT_DATA);
+
+    const fullChromeVersion =
+        userAgentBrowser.fullVersionOf(userAgentBrowser.Brand.CHROMIUM);
+    assertNotNullNorUndefined(fullChromeVersion);
+    assertEquals(
+        '91.0.4472.77',
+        fullChromeVersion.getIfLoaded().toVersionStringForLogging());
+
+    // Preload the full version list.
+    await userAgentBrowser.loadFullVersions();
+    // This should have no effect.
+    assertEquals(
+        '91.0.4472.77',
+        fullChromeVersion.getIfLoaded().toVersionStringForLogging());
+  },
 });
diff --git a/closure/goog/labs/useragent/highentropy/highentropydata.js b/closure/goog/labs/useragent/highentropy/highentropydata.js
index 14c76cc0b7..c1ff63fc81 100644
--- a/closure/goog/labs/useragent/highentropy/highentropydata.js
+++ b/closure/goog/labs/useragent/highentropy/highentropydata.js
@@ -12,6 +12,39 @@ goog.module('goog.labs.userAgent.highEntropy.highEntropyData');
 
 const {HighEntropyValue} = goog.require('goog.labs.userAgent.highEntropy.highEntropyValue');
 
+/**
+ * fullVersionList is currently not implemented in Chromium.
+ * TODO(user): When fullVersionList is added, remove this value.
+ */
+let fullVersionListAvailable = false;
+
+/**
+ * A helper function to check whether fullVersionList is available in the
+ * current browser.
+ * TODO(user): When fullVersionList is added, move hasFullVersionList()
+ * to browser.js, and inline the browser version check. For example, if it is
+ * implemented in Chromium 101, have hasFullVersionList simply return
+ * `browser.versionOf(CHROMIUM) >= 101`.
+ * @return {boolean}
+ */
+function hasFullVersionList() {
+  return fullVersionListAvailable;
+}
+exports.hasFullVersionList = hasFullVersionList;
+
+/**
+ * A test-only function to set whether it should be assumed fullVersionList is
+ * available in the browser.
+ * TODO(user): When fullVersionList is added, remove this function, as
+ * behavior when fullVersionList is either present or absent would be testable
+ * by setting the user agent and user agent data accordingly.
+ * @param {boolean} value
+ */
+function setHasFullVersionListForTesting(value) {
+  fullVersionListAvailable = value;
+}
+exports.setHasFullVersionListForTesting = setHasFullVersionListForTesting;
+
 /**
  * @type {!HighEntropyValue<!Array<!NavigatorUABrandVersion>>}
  */