The largest and most powerful of Romulan spacecraft, first detected in late 2364 by the Federation in the first Romulan meeting in 53 years.

Nearly twice the length overall of a Galaxy-class starship, this vessel used an artificial quantum singularity to power its warp-drive system. Decks are lettered and sections numbered. Some quarters are on C deck; Launch Bay 3 is on Deck E, Section 25. It carries at least three shuttlecraft areas, known as "Launching Bays." Even through a cloak, warp signature may be detected at speeds above warp 6.

Romulan warbirds have also been spotted in the following instances:

An unspecified Romulan warbird, bent on destroying Deep Space Nine and the wormhole as a catastrophic Dominion defense, was detected while cloaked. Due to the temporal waves emitted by its quantum singularity power source, O'Brien's radiation poisoning and his time-shifting resulted; In 2371, Tain used a warbird as his HQ during his planned invasion of the Dominion homeworld, an invasion made of a joint, covert Obsidian Order/Tal Shiar alliance bent on attacking the Founders. This warbird also found Constable Odo and Garak's Runabout near Unefra III.

A Romulan warbird was used as an adversary in Tuvok's Maquis-boot-camp battle simulation.

In 2379, the Enterprise-E encountered the new design of warbird, this one having both a more streamlined design and an extended wingspan than its counterpart's. The Valdore lead a small fleet of warbirds to intercept Reman Shinzon, in an effort to stop his plan to destroy Earth.

The warbirds joined forces with the Enterprise-E and their mission was a success.