The Brand New, Unlocked Sony Ericsson XPERIA X1 is a horizontal slider phone based on Windows Mobile 6.1 Operating System. It is Sony Ericsson's first mobile phone to feature Windows Mobile. The phone features a three-inch touchscreen overlaying a QWERTY keypad which emerges when the user slides the touchscreen face upward, much as in the HTC TyTN II, although the X1's touchscreen slides out in an arc. Its touchscreen is a 65,536-color TFT WVGA display. It has a 3.2 megapixel digital camera which records video at thirty frames per second in VGA (640x480) quality. There is also a secondary front facing camera for videoconferencing that is of QCIF format. It features a variety of connectivity options: mini-USB; wireless LAN 802.11b/g; Bluetooth 2.1 with A2DP, FTP, and HID; EDGE; and quad-band GSM, UMTS, HSDPA, HSUPA, and HSCSD.

The X1 has 400MB of internal memory, which is expandable using High Capacity microSD cards. The phone also features A-GPS for navigation. Due to the restrictions of Windows mobile, the phone will be the first business phone by Sony Ericsson which is not able to utilize the GSM network feature Alternate line service. Several software features will come standard on the X1, such as handwriting recognition software similar to Palm OS's Grafitti software (handwriting may be by an included stylus), an integrated aggregator for viewing RSS feeds, and push email. The device is powered by Qualcomm's ARM 11 MSM7200A CPU, which runs at 528Mhz. It has 256MB of RAM.