In Indonesia Amazon would be up against popular online sellers including Alibaba Group Holding Ltd. subsidiary Lazada Group, Tokopedia—backed by Sequoia Capital and SoftBank Corp. —and Shopee, an offering from Singapore-based Sea Ltd.

“There’s a lot of growth and a lot of competition,” said Usman Akhtar, a Jakarta-based partner with Bain & Company. There are also logistical challenges, he said. Indonesia comprises more than 17,000 islands.

But with a young and mobile-savvy population, “the growth is very fast and showing no sign of slowing.”