diff --git a/src/PhoneNumberUtil.php b/src/PhoneNumberUtil.php
index b900ebb4..e12915ef 100644
--- a/src/PhoneNumberUtil.php
+++ b/src/PhoneNumberUtil.php
@@ -164,6 +164,13 @@ class PhoneNumberUtil
      */
     protected static $GEO_MOBILE_COUNTRIES_WITHOUT_MOBILE_AREA_CODES;
 
+    /**
+     * Set of country codes that doesn't have national prefix, but it has area codes.
+     *
+     * @var array
+     */
+    protected static $COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES;
+
     /**
      * Set of country calling codes that have geographically assigned mobile numbers. This may not be
      * complete; we add calling codes case by case, as we find geographical mobile numbers or hear
@@ -400,6 +407,9 @@ protected function __construct(MetadataSourceInterface $metadataSource, $country
         static::$GEO_MOBILE_COUNTRIES_WITHOUT_MOBILE_AREA_CODES = array();
         static::$GEO_MOBILE_COUNTRIES_WITHOUT_MOBILE_AREA_CODES[] = 86; // China
 
+        static::$COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES = array();
+        static::$COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES[] = 52; // Mexico
+
         static::$GEO_MOBILE_COUNTRIES = array();
         static::$GEO_MOBILE_COUNTRIES[] = 52; // Mexico
         static::$GEO_MOBILE_COUNTRIES[] = 54; // Argentina
@@ -873,14 +883,18 @@ public function getLengthOfGeographicalAreaCode(PhoneNumber $number)
         if ($metadata === null) {
             return 0;
         }
+
+        $countryCallingCode = $number->getCountryCode();
+
         // If a country doesn't use a national prefix, and this number doesn't have an Italian leading
         // zero, we assume it is a closed dialling plan with no area codes.
-        if (!$metadata->hasNationalPrefix() && !$number->isItalianLeadingZero()) {
+        // Note:this is our general assumption, but there are exceptions which are tracked in
+        // COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES.
+        if (!$metadata->hasNationalPrefix() && !$number->isItalianLeadingZero() && !in_array($countryCallingCode, self::$COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES)) {
             return 0;
         }
 
         $type = $this->getNumberType($number);
-        $countryCallingCode = $number->getCountryCode();
 
         if ($type === PhoneNumberType::MOBILE
             // Note this is a rough heuristic; it doesn't cover Indonesia well, for example, where area
diff --git a/tests/core/PhoneNumberUtilTest.php b/tests/core/PhoneNumberUtilTest.php
index e66c7fe7..7f459c12 100644
--- a/tests/core/PhoneNumberUtilTest.php
+++ b/tests/core/PhoneNumberUtilTest.php
@@ -333,6 +333,9 @@ public function testGetLengthOfGeographicalAreaCode()
         $this->assertEquals(1, $this->phoneUtil->getLengthOfGeographicalAreaCode(self::$auNumber));
 
         // Italian numbers - there is no national prefix, but it still has an area code.
+        $this->assertEquals(2, $this->phoneUtil->getLengthOfGeographicalAreaCode(self::$mxNumber1));
+
+        // Mexico numbers - there is no national prefix, but it still has an area code.
         $this->assertEquals(2, $this->phoneUtil->getLengthOfGeographicalAreaCode(self::$itNumber));
 
         // Google Singapore. Singapore has no area code and no national prefix.