The Dominion War, primarily depicted in Star Trek: Deep Space Nine, plunged the Star Trek universe into chaos. Lasting from 2373 to 2375, it saw old enemies join forces against the Dominion, a powerful Gamma Quadrant civilization. The Federation Alliance (comprising Starfleet's forces, as well as the Klingons and Romulans) secured victory, but the war was hard-fought.
Although some of the conflict's most brutal battles took place on the ground, on planets like AR-558, many key engagements occurred in space. The Dominion War forced the pacifistic Federation to produce warships rather than purely scientific vessels. The fact that Starfleet was willing to shift its exploratory focus to a war footing underlines the scale of the threat posed by the Dominion — not just to the Federation, but to the entire Alpha Quadrant.
8 USS Odyssey
Starfleet and its allies would lose hundreds of ships while repelling the Dominion and its Cardassian allies. However, the first of Starfleet's losses occurred prior to the outbreak of the conflict, when the USS Odyssey was destroyed by the Jem'Hadar in 2370. The Odyssey, under the command of Captain Keough, entered the Delta Quadrant to investigate the Jem'Hadar threat and liberate Commander Sisko from their clutches.
Although the Odyssey's civilian population were evacuated prior to the vessel's destruction, the loss of the Galaxy-class starship was a turning point in Starfleet's history, and showed the need for a capable fighting force if the Dominion was to be countered.
7 USS Centaur
One of Star Trek's strengths is its visual storytelling. From the clean, warmly lit interiors of the Enterprise-D, which demonstrate the Federation's utopian nature, to the grungy decks of Klingon vessels, Star Trek conveys information without relying on dialogue. The USS Centaur continues this tradition, telling fans about Starfleet's condition during the Dominion War.
The Centaur combines an Excelsior-class saucer section and nacelles with Miranda-class components. It would not be the only kitbashed design to fight in the Dominion War. The so-called Frankenstein fleet showed Starfleet's intense need for ships of any type or design, no matter how strange. However, the Centaur-class would be one of the more enduring kitbashes, as it offered the template for the hero ship in Dramatic Labs' Star Trek: Resurgence.
6 USS Sitak
One of the Miranda-class starships employed by Starfleet to bolster its forces during vital engagements like Operation Return, the USS Sitak shared a fate in common with many ships of its type: destruction. With the help of the similarly doomed Miranda-class USS Majestic, the Sitak escorted Captain Sisko's USS Defiant through a Dominion blockade. The Sitak's sacrifice was not in vain, as the Defiant was able to reach and liberate Deep Space Nine.
The Miranda-class (first seen being taken over by the titular villain of 1982's Star Trek II: The Wrath of Khan) entered service in the 2260s, over a century before the events of Deep Space Nine. As such, it's unsurprising that Starfleet's aging workhorse struggled to compete in the Dominion War.
5 USS T'Kumbra
Even with the Dominion War raging, Deep Space Nine found time to tell more lighthearted stories. Season 7's "Take Me Out to the Holosuite" pits the crew of DS9 not against the Dominion or Breen, but rather against the crew of the USS T'Kumbra, a Nebula-class starship crewed entirely by Vulcans. The battleground: a baseball pitch. Although Solok's team defeats Sisko's "Niners," the Niners celebrate their single point nonetheless, raising a toast to "manufactured triumph."
Despite its arrogant crew, the T'Kumbra made a large contribution to the war effort. Before its visit to Deep Space Nine, the starship spent six months on the front lines, earning Solok his second Christopher Pike Medal of Valor.
4 USS Hood
The USS Hood is one of Star Trek's most prolific background vessels. Both William Riker and Geordi La Forge served on the vessel prior to their postings on the Enterprise-D, while the Hood also joined Captain Picard's task force during the Klingon Civil War. It also appeared in animated form in Star Trek: Lower Decks.
This Excelsior-class starship fought throughout the Dominion War, including in Operation Return and the First Battle of Chin'toka. Although the Excelsior design (first seen in Star Trek III: The Search for Spock) was nearly a century old by the time of the Hood's engagements with the Dominion, the vessel survived the conflict.
3 USS Prometheus
The experimental USS Prometheus was equipped with a multi-vector assault mode, allowing the starship to split into three smaller attack vessels. The Nebula-class USS Bonchune was easily disabled by the Prometheus after Romulans captured the latter ship in the Star Trek: Voyager episode "Message in a Bottle."
Although it's uncertain whether the Prometheus actually engaged Dominion forces, the timeframe of "Message in a Bottle" (2374) means that the ship was active during the conflict. Its appearance in Voyager's finale as part of a force defending Earth from a Borg sphere suggests that it may have been assigned to guard the planet, perhaps seeing combat during the Breen's surprise raid on Starfleet Headquarters in 2375.
2 USS Enterprise-E
Captain Jean-Luc Picard's Enterprise-E may have been the flagship of the Federation during the Dominion War, but the ship and crew were absent from many of the conflict's key engagements. This was perhaps a consequence of its captain's diplomatic skill-set. The questionably canonical "The Gorn Crisis" comic sends the Enterprise-E on a diplomatic mission to the eponymous lizards with the goal of forming an alliance against the Dominion.
Fans would glimpse the Sovereign-class starship's involvement in the conflict during the events of Star Trek: Insurrection (1998). Picard and his crew become caught up in the conflict between the agrarian B'aku and the villainous Son'a for control of a planet with restorative properties, which the Federation hopes to use as part of its own war effort.
1 USS Defiant
Originally designed to combat the Borg threat, Starfleet's original dedicated warship was the first vessel to encounter the Dominion's Founders and participated in many key battles against their forces. It was instrumental in laying mines around the Bajoran Wormhole, preventing further Dominion reinforcements, and also liberated DS9 during Operation Return. Although the original USS Defiant was destroyed by the Breen, a second Defiant was soon commissioned.
The Defiant-class represented a radical divergence from conventional Starfleet design principles. It also employed a cloaking device, normally forbidden under the Treaty of Algeron. Yet despite its unusual appearance and specifications, the Defiant remains an iconic ship. The second Defiant has since appeared in Star Trek: Prodigy and was preserved at the Fleet Museum in Star Trek: Picard.