https://www.cnet.com/news/making-the-holodeck-a-virtual-reality/ > Data (Brent Spiner) and Capt. Picard (Patrick Stewart) explore a virtual San Francisco in Star Trek: The Next Generation > A version of the holodeck first appeared as the "recreation room" in 1974 in the "Star Trek: The Animated Series" episode "The Practical Joker." It wasn't until 1988 in the Star Trek: The Next Generation episode "The Big Goodbye" that the holodeck played a central part of the plot.