Temporal transporters, are employed on ships and allows for near-instantaneous travel through both time and space. From the layman's point of view, it does not appear very different from the standard transporter technology utilized by the Federation since the 22nd century; the person to be transported steps onto a platform, and dematerializes, to rematerialize elsewhere - except in this case, it is also elsewhen.
However, this technology is not without its dangers, or at least, in the version used by the Wells-class USS Relativity. Temporal psychosis often set in within just a few such transportations, potentially killing the subject. However, even death is not fatal; the subject can simply be snatched out of time before any transportations even occurred, effectively negating the damage. (VOY: "Relativity") It is also not unreasonable to believe that, given the apparent frequency of temporal transportations in the 31st century as experienced by Enterprise and its dealings with temporal agent Daniels, that the spectre of temporal psychosis has been, by then, banished. (ENT: "Azati Prime")
The power of temporal transporters is not fully understood. It is known for sure that they are able to transport at least nine hundred years away from the 31st century to the 22nd (ENT: "Azati Prime"); however, spatial range is nearly unknown, save that it can transport people over distances that Enterprise covered in relation to Earth. (ENT: "Shockwave, Parts I and II")
Prior to using temporal transporters, it appears to be common practice for parties interested in travelling through time to send an entire vessel called a timeship. One such ship was the Aeon, which used some form of temporal drive to create traversable temporal rifts. (VOY: "Future's End, Part I and Part II")
The theoretical Krenim temporal weapon ship utilizes temporal shields to shield itself from any possible historical repercussions the crew may create; for instance, preventing your ship from ever existing may jeopardize a mission. (VOY: "Year of Hell, Part I and Part II")
- Wells-class timeships apparently are equipped with temporal shields as well, to the same effect as the Krenim ship. Wells-class timeships also have a temporal displacement drive, which presumably also allows the entire vessel to generate temporal propulsion and thus travel through time if required.