Is there any canon information about non-Federation ships having holodecks? I could definitely see Hirogen, Klingon, Kazon, and Jem'Hadar ships having holodecks, but I'm not sure about these or the vessels of other species.
At least three species have holodecks (or at least the ability to build holodecks) on their ships.
The Xyrillians encountered by the Enterprise NX-01 in ENT: "Unexpected" had some version of holodeck technology, though whether it worked on the same principles as Federation ships is unclear.
The Xyrillians later shared the holodeck technology with the Klingons (going so far as to install a holodeck on a battle cruiser), so at least one Klingon ship had a holodeck. It's not unreasonable to expect that future Klingon ships made use of holodecks.
Riker ends up on a simulation of a Romulan holodeck in TNG: "Future Imperfect", though that holodeck was supposedly situated on a Romulan base rather than a ship. Riker's lack of surprise at being on Romulan holodeck shows it's not improbable that ships had them as well.
A review of the psychology of the Alpha Quadrant would likely reveal the holodeck/holosuite technology is at least available to any species capable of warp travel to meet its power requirements, has replicator and transporter technology to create objects, and force field generation to produce the physical illusion of movement.
A deactivated holodeck showing just the empty room awaiting input from the user.
Whether they use it depends on their psychological, technological and cultural propensity for immersive virtual entertainment.
The Holodeck is an energy intensive technology using force fields, replicators and considerable computational capacity to create virtualized environments, complete with real-time sensory stimuli based on interpolated information from those environments.
With the power requirements, it makes sense such technology will be restricted to planets, space stations and starships with the capacity for excess energy and computational capacity to be available.
Having a starship does not mean a ship will have a holodeck. Dedicated warships will probably not have one, as such technology would be a drain on ship's resources and require personnel to maintain that technology. Of the primary races of the Star Trek series, some species are more likely to utilize the technology while underway than others.
- Starfleet personnel use holodecks for training, diagnostics and recreation. Holodecks are used to recreate or simulate settings and events for analysis, such as to explore the forensics and logistics of a crime scene for law enforcement purposes, or for scientific experimentation.
- In general, the holodeck "functions as a cultural repository of narrative possibilities that would normally be excluded from the ship's own socio-historical moment" and "allows the Enterprise community to include even that which it excludes by containing the excluded within a proper, controlled place which in no way intrudes upon the everyday space of the ship. -- Wikipedia, Holodeck
- Federation ships whose crews maintain long rotations in deep space will likely have one. Since the ship is stationed far from Federation territory, a holodeck is an excellent psychological resource for maintaining crew morale.
Klingon ships, given the warlike nature of the Klingons and their relatively spartan lifestyles, would forgo such a luxury on their ships but might partake of the technology in a space station or during their shore leave. Klingons fight hard and party hard, but usually not at the same time. Hardship while underway would be considered part of a toughening ritual so the holodeck would likely be seen as an unnecessary luxury.
Cardassian ships are primarily warships and only the largest of them MAY have a holodeck onboard. Since Deep Space Nine had a holosuite facility, we know the Cardassians are familiar with the technology, but probably wouldn't use it on their ships for fear of softening their men. Rigidly disciplined, such technology would be reserved for the highest order of officers, and no one else.
Romulans have holodecks on their larger ships, used more than likely for the same psychological purposes as the Federation. Romulan warships would spend years patrolling territories under cloak. It would make sense they would have need of psychological training and outlets the holodeck makes possible.
Vulcans would likely have holodecks, but I suspect their use of them may be more for virtual experimentation of the type LaForge did during the Leah Brahms episode, Booby Trap, than personal enjoyment. Not saying Vulcans can't enjoy the physical benefits of a holodeck but I suspect they would be less inclined to admitting it.
Ferengi starships are likely to include holodecks since the Ferengi are at least partially hedonistic and adverse to leaving home without as many comforts as possible. Their ships are large and powerful ensuring there is plenty of energy for oo-mox.
We can assume the Jem'Hadar had no use for such technology as holodecks seeing how their entire existence was reserved for serving the Founders and engaging in battle on their behalf. They did not appear to have much in the way of imagination or personal lives, so the holodeck would be a technology they would have little use for, except perhaps for physical training purposes.