An over-the-air update to the Samsung Galaxy S4 with Sprint Spark, Sprint's faster 4G LTE network, will make it possible for travelers to call home over any Wi-Fi network, at no additional cost.

The International Wi-Fi calling feature will work in over 100 countries, supporting calls made to phone numbers in the United States, US Virgin Islands, and Puerto Rico.

While the Galaxy S4 is the first phone to kick off Sprint's new program, the carrier will continue to add devices in 2014 that also support Wi-Fi calling. The software rollout begins on Aug 28.