The Sony Ericsson K800, and its variant, the Sony Ericsson K790, are the latest cell phones of their class from Sony Ericsson. The phones are the successor to the Sony Ericsson K750i. Both of the phones feature a 3.2 megapixel digital camera complete with a xenon flash, a protective lens cover, and a new "BestPic" bracketing feature, and are the first to be tagged with the Sony Cyber-shot branding.

The new "BestPic" feature takes 9 full quality snapshots of a subject in quick succession, allowing the user to choose the best shots from them. On the entertainment front, the phones have a media player supporting MP3, AAC/AAC+/eAAC+ and WMA music files and 3GP/MPEG-4 video files. The phones also feature a FM radio, and a Memory Stick Micro (M2) slot for expandable memory.

The K800 is the only one to feature a QCIF (176X144) resolution front-mounted camera for 3G video conferencing. According to the official Sony Ericsson specifications, the K800's talk time drops steeply from around 7 hours when using GSM to about 2 hours 30 minutes whilst using UMTS.