Latest OxygenOS beta update features OnePlus Roaming, as in unlimited data in Japan for $3.50 a day
The other new feature is pretty awesome for those who travel abroad and puts OnePlus on equal footing with other Chinese makers like Huawei or Xiaomi which have had this for a while now. Called OnePlus Roaming, it lets you choose a prepaid data package before you land in a foreign country, and boom, you've got data without having to search for carrier kiosks or haggle with the locals at the airport for a prepaid SIM card in the middle of the night.
The data package prices vary, of course, depending on the contracts that the provider of the OnePlus Roaming service has with the local carriers but they are usually way, way lower than what US carriers would charge you for roaming abroad. For instance, you can get unlimited 4G LTE data in Japan for $3.5/day, as you can see in AP's screenshot here, or get 8 days of unlimited for $23. There are usually at least two or three options to pick from, from weekly to PAYG deals.
Things that are NOT allowed: