The following is a table of the survivors and which station or stations they have visited. The table features survivors of the crash (without Walt, because we don't know which stations he visited when the Others kidnapped him) and Desmond, who joined the Losties. Danielle is also listed here, though she may have knowledge of DHARMA stations that has been unrevealed.
The Hatch was originally discovered, and uncovered, by Boone and Locke. Template:Crossref
The interior was first seen by Kate, Locke and Jack. Template:Crossref
By the end of Season 2, most of the main characters have been shown inside the station on the show. Also, it is taken as common knowledge that all the other survivors know about the Swan station due to Locke's statement at one time that the rotation list for the button had "everyone" on it. Template:Crossref
Desmond predicted that Charlie had to go here to flip the yellow switch so they could get rescued. He said Charlie would swim down and drown. Desmond offer to go instead but Charlie knocked him out with a paddle.
Charlie swam down to the station to find it not to be flooded. After being briefly held hostage, he completed his mission, and Mikhail detonated a grenade from outside one of the portholes, flooding the communications room. Template:CrossrefTemplate:Crossref
Daniel and Charlotte went to The Tempest in order to shut it down, so that Ben could not use the toxic gas against everyone on the island. They were followed by a suspicious Juliet, Jack, and Kate. Template:Crossref
Most stations visited
Kate has visited the most DHARMA stations, having been in four; the Swan, the Staff, the Flame and both the above-ground level of the Hydra and the aquarium where Jack was held.
Sayid has also visited four DHARMA stations, although one was the apparent decoy station, The Door. The others visited are The Swan, The Pearl, and The Flame.
Most experienced travelers
The most experienced travelers in terms of DHARMA stations are:
Kate could be considered the most experienced survivor, because she has visited the most stations out of all of the survivors. The only three stations she has not visited are the Pearl, the Arrow, and the Looking Glass. Visiting the Arrow station, however, would give her little, if any, additional knowledge of The Others, because she is already aware that they wear costumes. She is also one of the few survivors to have seen The Others' Barracks.
Locke is an experienced survivor. He did briefly see the blast door map, meaning he has potentially more knowledge than all the other explorers combined (though the fact remains he remembers very little of what was drawn on the door and was later more interested in running the timer down to zero than seeing more of the map. While he has been exposed qualitatively to more information than any other survivor, his mystical attitude toward the Island leads to him taking little advantage of the information. When presented with a wealth of new information at the Flame, his response was to destroy everything.
Sayid is also reasonably experienced, having explored the Swan, the Pearl and the Flame in much detail - searching the underground tunnels of the Swan, checking out the electronics of the Pearl and looking through some of the files at the Flame. But he shows little interest in gathering information outside his immediate personal objective.
Michael is also reasonably experienced, having not only visited the Arrow and the Swan, but also being aware of the the Door and the Staff stations.
As well, counting "non-Others", Kelvin and Radzinsky's exploring led them to several of the stations identified on blast door map. They appear to have been to the Swan, the Staff, the Arrow and the Flame. The map indicates they did not reach the Pearl but knew the station existed.
The following is a table of the Others and which station or stations they have visited. The table lists all Others who have been known to visit at least one station. Due to the fact that the show has not followed the Others as thoroughly as the survivors, there may be Others who have visited stations off-screen, despite the fact they are listed as 'not visited'. It is also harder to note which stations each Other does know about - thus, each Other will only be listed as either 'Visited' or 'Not visited' each station.
Ethan took Claire to the Staff in order to retrieve her unborn baby. Tom was also present at this time. Alex would later save Claire from her fate. Template:Crossref
Juliet took Sun to the Staff in order to determine a D.O.C. (Date of Conception) for her unborn baby. The Staff was also where Juliet left her recorded messages for Ben whilst she infiltrated the survivors. Template:Crossref
Ethan, Goodwin and Sabine were seen in the operating room in Juliet's flashback. Template:Crossref
Ben and Juliet have visited the most DHARMA stations, having been in 5 each as of the Tempest. They may have at some point also visited the other stations, but it has not yet been shown. Following them is Tom, who has been in three stations.
Richard Alpert, Ryan Pryce, and the non-recurring characters Amelia and Adam are the only named Others who have never been confirmed visiting or hearing of a Station.
Jacob also has no confirmed knowledge of any Stations, though his name is mentioned in outtakes from the Orchid's orientation video, and in a "brainwashing" video played in the Hydra's Room 23.