diff --git a/packages/localize/src/number/formatNumberToParts.js b/packages/localize/src/number/formatNumberToParts.js
index 7f01c5816..bff073212 100644
--- a/packages/localize/src/number/formatNumberToParts.js
+++ b/packages/localize/src/number/formatNumberToParts.js
@@ -61,7 +61,7 @@ export function formatNumberToParts(number, options) {
         formattedParts.push({ type: 'integer', value: numberPart });
         numberPart = '';
       }
-      const decimal = getDecimalSeparator();
+      const decimal = getDecimalSeparator(computedLocale);
       if (formattedNumber[i] === decimal) {
         formattedParts.push({ type: 'decimal', value: formattedNumber[i] });
         fraction = true;
@@ -71,7 +71,7 @@ export function formatNumberToParts(number, options) {
     }
     // detect literals (empty spaces) or space group separator
     if (regexSpace.test(formattedNumber[i])) {
-      const group = getGroupSeparator();
+      const group = getGroupSeparator(computedLocale);
       const hasNumberPart = !!numberPart;
       // Write number grouping
       if (numberPart && !fraction) {
diff --git a/packages/localize/test/number/formatNumberToParts.test.js b/packages/localize/test/number/formatNumberToParts.test.js
index d3aa21a42..4fcc45c2e 100644
--- a/packages/localize/test/number/formatNumberToParts.test.js
+++ b/packages/localize/test/number/formatNumberToParts.test.js
@@ -33,9 +33,9 @@ describe('formatNumberToParts', () => {
 
     specs.forEach(([locale, currency, amount, expectedResult]) => {
       it(`formats ${locale} ${currency} ${amount} as "${stringifyParts(expectedResult)}"`, () => {
-        localize.locale = locale;
         expect(
           formatNumberToParts(amount, {
+            locale,
             style: 'currency',
             currency,
           }),
@@ -60,9 +60,9 @@ describe('formatNumberToParts', () => {
 
     specs.forEach(([locale, currency, amount, expectedResult]) => {
       it(`formats ${locale} ${currency} ${amount} as "${stringifyParts(expectedResult)}"`, () => {
-        localize.locale = locale;
         expect(
           formatNumberToParts(amount, {
+            locale,
             style: 'currency',
             currencyDisplay: 'code',
             currency,