Following the Romulan/Klingon conflicts of the 2340's, the Federation launched a new defense initiative to reinforce their borders in case of possible Romulan aggression. The R2 Defense Starbase design was the result of engineering modifications and enlargement of the basic R1 Outpost class. The increase in size allowed the R2 Starbase to mount several new weapons systems, including the new dual phaser array that had previously only been mounted on full-fledged Federation Starbases.
The R2 Defense Starbase network along the Federation border would prove an invaluable asset during the Dominion War. One of these bases, Starbase 357, was used as a key base for the Federation fleet on the Dominion Border.