Like earlier red hued products on the Cupertino-based company's lineup, a portion of sales from the red iPhones will be used to help fund HIV/AIDS research, Apple said on its website.
The red iPhones will have the same internals and pricing tiers as the black, gold, silver, rose gold and jet black that were launched late last year. The base storage, however, will start at 128 gigabytes like the jet black version.
It will be available in the United States starting on 24 March 2016. There was no immediate word on local availability.
Samsung's Galaxy S8 is expected to launch with a screen that occupies almost the entire front of the device and face recognition technology for mobile payments, features that are missing from the current iPhone line.
Phone manufacturers have been launching more colorful flagships. Google's Pixel and Pixel XL comes in a bright "really blue" option while Huawei's P10 and P10 Plus will be avialable in "greenery" and "dazzling blue," designed by Pantone.