About r/scifi
In its own words:
Science Fiction, or Speculative Fiction if you prefer. Fantasy too. Asimov, Bradbury, Clarke, Dick, Heinlein and other SF books. SF movies and TV shows. Fantasy stuff like Tolkien and Game of Thrones. Laser guns, space ships, and time travel. etc. Star Trek, Battlestar, Star Wars, etc.
Community guide
r/scifi (#205, about 4.5 million subscribers) is oriented around: Science Fiction, or Speculative Fiction if you prefer. Fantasy too. Asimov, Bradbury, Clarke, Dick, Heinlein and other SF books. SF movies and TV shows. Fantasy stuff like Tolkien and Game of Thrones. Laser guns,… Recent activity samples show 22 posts/day in recent samples (~44% text, ~31% image, ~14% gallery). A rules list was not in our snapshot—use the live sidebar before posting. Recent phrase samples include “patrick stewart”, “science fiction”, “short story”, “star trek”. Directory metadata files it under “Entertainment”.
What belongs here
Stay inside the room’s stated scope rather than adjacent off-topic dumps. Conversation lately clusters around patrick stewart, science fiction, short story, star trek, borg queen.
How it differs from lookalikes
Prefer this room when your post matches its description and rules—not merely a larger sibling community.
Practical pointers
Read the live sidebar/rules before posting; collected snapshots can lag. Common flairs in samples include: Original Content, General, Recommendations, Films.
SubMouse Editorial
The community was created on Jan 25, 2008, which makes it 18 years old. Since Oct 26, 2026, it has gained 1,157 subscribers (+0.03%). It sits just behind r/instant_regret (#204) and ahead of r/UnresolvedMysteries (#206) in our ranking.
What sets r/scifi apart
Its rhythm is strongly tied to time zones: the busiest hour (21:00 UTC) sees about 16.0× as many posts as the quietest (09:00 UTC).
Subscriber growth
Between Sep 19, 2026 and Nov 2, 2026, r/scifi grew from 4,498,591 to 4,507,100 subscribers (+8.5K, +0.19%). That is about 193 new members per day. The chart uses our weekly snapshots (9 so far), so it gets longer every week.
What r/scifi talks about
We read the titles of 153 recent posts (Oct 29–Nov 5), the words that come up most are “sci-fi”, “story”, “movie”, “book” and “sci”. Other frequent themes are actually, books, looking, recommendations, short and novel. Recurring phrases include “patrick stewart”, “science fiction”, “short story” and “star trek”. By format, 44% are text posts, 31% are images and 14% are galleries.
Popular post flairs: Original Content (55), General (34), Recommendations (19), Films (14), TV (9), Print (8).
Activity and best time to post
r/scifi gets about 23 new posts a day. The public archive holds 187,833 posts and 3,871,363 comments in total, about 20.6 comments per post. Last week the busiest day was Saturday (45 posts) and the quietest was Monday (10). Posting peaks around 21:00 UTC and is lowest around 09:00 UTC.
How to join
Open reddit.com/r/scifi and press “Join”. Read the community rules in the sidebar before you post: every subreddit is run by its own volunteer moderators.
Frequently asked questions
How many subscribers does r/scifi have?
r/scifi has 4,507,100 subscribers (Nov 2, 2026), which makes it the #205 safe-for-work subreddit in the SubMouse ranking. It added 8,509 members between Sep 19, 2026 and Nov 2, 2026.
How old is r/scifi?
r/scifi was created on Jan 25, 2008, so it has been around for 18 years. The oldest post in the public archive is from Jan 27, 2008.
How active is r/scifi?
Very active: r/scifi gets about 23 new posts a day (average of the last four weeks). Over its lifetime the archive counts 187,833 posts and 3,871,363 comments. In a sample of 153 recent posts we counted 141 different authors.
When is r/scifi most active?
Based on post counts from Oct 29, 2026 to Nov 4, 2026, the busiest day was Saturday and the quietest Monday, and most posts arrive around 21:00 UTC, with the fewest around 09:00 UTC. More posts also means more competition, so a quieter hour can help a post get noticed.
What is r/scifi about?
The community describes itself as: “Science Fiction, or Speculative Fiction if you prefer. Fantasy too. Asimov, Bradbury, Clarke, Dick, Heinlein and other SF books. SF movies and TV shows. Fantasy stuff like Tolkien and Game of Thrones. Laser guns, space …” Recent post titles often mention sci-fi, story, movie, book and sci. Most posts are text posts (44%).
Is r/scifi safe for work?
Yes. Reddit does not mark r/scifi as an 18+ (NSFW) community. SubMouse lists safe-for-work subreddits only.
How do I post on r/scifi?
Join the community on Reddit first, then use “Create post”. r/scifi accepts both text and link posts, with images, galleries and polls enabled. Moderators remove posts that break the rules, so read them in the sidebar before posting.
Which communities are like r/scifi?
Communities with similar topics include r/Fantasy (4M), r/worldbuilding (1.9M), r/StarWars (4.7M), r/PrequelMemes (3.8M) and r/horror (3.6M).
Stats from public data (data updated Nov 2, 2026; activity, rules and archive totals via the Arctic Shift archive, Nov 6, 2026). Point and comment counts are archive snapshots and can be lower than on Reddit today. SubMouse is an independent directory and is not affiliated with Reddit or the moderators of r/scifi.