Yuri!!! on Ice is a sports anime with a lot of handsome men/boys who have different personalities and relationship dynamics; and the other characters surprisingly show just as much Hidden Depths. Obviously, this leads to a lot of theories, potential backstories or future scenarios, and et cetera.
- Some fans believe that Yuri has some issues related to his weight and some self image issues whenever this is brought up, though fans like to believe that Victor finds Yuri's chubby body either adorable or sexy. Eventually, it's revealed that Victor finds it to be the former.
- Once it was revealed that Otabek had previously trained in Canada and the U.S., a lot of fans speculated that he might have been friends or, at least, known or shared a rink with J.J. Official material confirmed this, although it also mentioned that they drifted apart over the years.
- There are several fans (with some merit) who like to portray Phichit as a Shipper on Deck to Victor/Yuri which actually becomes canon considering his reaction to their engagement in Episode 10.
- J.J. had been speculated to be a devout Christian by fans, due to him crossing himself before skating. It was later confirmed by Sayo Yamamoto in an interview, along with that J.J. and Isabella are saving sex for after marriage.
- Some fans believe Phichit and Yuri had a romantic and/or sexual involvement while they were roommates or that Phichit had a crush on Yuri.
- Plenty of people like to think that Christophe wants to sleep with Victor or Yuri. Or both. There's also an almost unanimous belief that, at one point or another in the past, Christophe and Victor have slept together.
- While Victor and Chris are shown to be friends and have a history together in the show, the "best friends who are always calling each other and asking for advice on their relationships" part is largely invented by the fandom. In particular, a lot of fanworks suggest that Victor confided in Christophe about his feelings for Yuri after the banquet. To a certain degree, this is also true of how fanworks interpret Yuri's friendship with Phichit; while they do consider each other their best friends, Yuri seemingly didn't call Phichit for months after he left Detroit, and first does it in order to ask a favor.
- Some fans tend to theorize that besides Yuri grinding on Victor in Episode 10, they had a one night stand afterwards, or came close to it, since it would cause Victor's unusually forward manner of displaying physical affection (which can get a little overboard at times) to make much more sense.
- There's a pretty intense fan discussion about whether The Big Damn Kiss was Yuri and Victor's actual first kiss or just their first public kiss. Given Yuri's increasingly receptive and comfortable attitude toward Victor's handsier and more flirtatious behavior, especially in public (like Victor getting half-naked and basically molesting Yuri after too many drinks before the Cup of China), some fans have speculated that they were already in a sexual relationship several episodes before their official Relationship Upgrade. It doesn't help that with a bit more knowledge of Japanese, it's clear that several commentators and other skaters already think the two are involved.
- Many fans believe that Yuri was a virgin before his Relationship Upgrade with Victor. Several characters in the show tease him about his lack of a love life, so it wouldn't be that surprising.
- Fans at least generally agree that Victor is his first serious relationship. Those who don't see Yuri as a virgin tend to think he got it out of his system through drunken one-night stands or friends-with-benefits type situations (possibly with Phichit). This seems supported by the teasing Yuri gets about his lack of relationship experience.
- While Victor confirms that he had previous relationships, a lot of fans think Yuri is his first serious relationship or at least, his first time falling in love. The latter seems to be supported by Victor talking about "neglecting life and love for 20 years" in episode 10.
- Yuri is often portrayed as a Sex God in fanworks, probably due to a combination of his eros persona, his Launcher of a Thousand Ships status, Victor's mention of his stamina, and of course, the pole-dancing.
- A lot of people believe that Yurio calls, or will call, Otabek by the nickname "Beka", a common nickname in Kazakhstan for men with names finishing in "bek". Similarly, people believe that when he grows older, his hair will become increasingly longer, possibly even with some braids and will grow taller than Otabek. Similarly, some believe that Otabek would call Yurio "Yura" or "Yuratchka".
- Fans tend to agree that after their careers end, the most likely thing is that Yuri would start teaching skating for young kids while Victor would start coaching older kids. To a lesser degree a lot of people believe they'll have two kids, possibly twins.
- A lot of people have become more and more interested in the idea that Victor and Lev Haiba are related, due to the fact that they're both Russian (half in Lev's case), and have short, light gray/silver hair. It helps that the the fandoms of both series are good friends (see Friendly Fandoms below).
- It's fairly common in both the Japanese and English-speaking fandoms to portray Yurio as an older brother figure towards the Nishigori triplets, since he's already friends with their mother Yuko (and this is partly fueled by Yuko texting Yurio a photo of both of them with the triplets in Episode 4).
- It's often theorized that Mari used to take ballet lessons from Minako but lost interest, leading Minako to teach Yuri instead.
- While this may go into WMG territory, several fans claim that the Barcelona Grand Prix Final was rigged, since the official material containing the scores to the characters' programs (particularly with Yuri and Yurio) do not match up to the scores shown in the series, and there is no way that it could have been a mistake on the writers' part.
- Japanese fanon tends to portray Yuko as a Yaoi Fangirl who nosebleeds over any romantic interactions between Yuri and Victor. In canon, the only times she gets a nosebleed are just over Victor, who she's a a big fan of (once when he sends a smolder her way when he's demonstrating the Eros program, and again when she sees Yurio wearing one of Victor's old costumes).
- The exact sexualities of characters are not mentioned in-series, however Everyone Is Gay is the default for most of the cast. If a character has shown attraction to the opposite gender then they're depicted as bisexual.
- The question of if Yuri is gay or bisexual actually leads to a lot of arguments in the fandom, mostly depending on how people interpret his skating for Yuko in episode 1. On the other hand, it seems generally agreed-upon in the fandom that Victor is completely gay, because of his general flamboyant demeanor as well as the visual references in his costumes to famous gay figure skaters such as Johnny Weir and Jeffrey Buttle.