Bathtub Scene

One of the most simple forms of Fan Service is having an attractive female or male spend a small amount of screen time in the tub. Many films usually use this as an easy excuse for nudity. Even though they are not very necessary, Bathtub scenes usually seem to sneak their way into many forms of media even though they are most of the time unnecessary to the plot.

When a bubble bath is involved, the Bath Kick is usually close by. Censor Suds usually come in. This trope is a variation of the Shower Scene. See Furo Scene for the Japanese variation.

Anime & Manga

 * Blair from Soul Eater first appears in a bubbly bathtub scene in which Soul lands in her bathtub during the first episode.
 * Blair has another in episode 4.
 * Tsubaki has one in a wooden bathtub in episode 14.
 * Tower of God, chapter 89: the (mostly) male cast of Season 2 has a bath and massage session, all for the purpose of characterization and foreshadowing. No, seriously.
 * Zoids Genesis has many with the Bathing Beauty Colonel Felme who even has bathed in an Awkwardly Placed Bathtub.
 * Many episodes of Maicchingu Machiko Sensei include a scene with the title character in the bath tub. One scene involved one of her students attempting to join her. Yeah, it's that kind of an anime.
 * In the second episode of Zero Zero Nine One, main protagonist Mylene Hoffman is taking a bubble bath, but is interrupted and sent on a mission.
 * A Little Snow Fairy Sugar always ends with tween Saga and the titular character sharing a bubble bath as they reflect on the events of the episode. The Censor Suds keep it clean.
 * Bulma from Dragonball has a bubble bath in the second episode and is then seen naked by Goku, who makes comments about her cleavage, which is covered by the bubbles, and says it looks like a butt. She also has one in a filler scene in episode 49 of Dragon Ball Z during the Frieza Saga where she is in a capsule house in the bathtub talking to her father on a radio.
 * In the wartime Girls Love manga series Kurogane Pukapuka Tai, there's an unwilling one where stinky U-Boat captain Nina Stortebeker is hauled off and thrown in the tub before being scrubbed with a long-handled broom. Played for fanservice, naturally.
 * Pretty much every episode of Hidamari Sketch contains someone having a bath. It's usually Yuno, but it has been Sae, Hiro, Miyako, and Yoshinoya-sensei. One episode had short snippets of each one singing part of the first season theme song, but most often, whoever it is says something referring to what happened.
 * By contrast, such scenes are few and far between in the manga.
 * In Sailor Moon Esmeraude had a bathscene where she was talking to her boss. A lot is actually shown, in comparison to her closed-up outfit.
 * The vampire villain, Camula, has a short scene in the bath after she sends her bats to spy on various duellists in Yu-Gi-Oh GX. Her entire role is very much played for fanservice, being the only attractive female to appear up to that point (except Asuka).
 * Would you believe there's an entire wiki devoted to this trope? Ain't the internet great?

Films -- Live-Action

 * Slither has one which is used a lot as promotion for the movie (being the only reason to see it).
 * The title character of Carrie has a bathtub scene in the 1974 version, where she washes all the pig's blood off her in the bathtub equivalent of a Shower of Angst.
 * There's a bathtub scene in Pretty Woman for Julia Roberts to enjoy the five-star accomodations, that works kinda sorta as Fan Service, though only her head and one of her legs are showing for most of the scene.
 * In The Truth About Cats and Dogs, Janeane Garofalo and Ben Chaplin have a phone conversation, each in a separate bubble bath. In this case, the Censor Suds also cover Garofalo's tattoos.
 * Short Circuit has Ally Sheedy (as Stephanie Speck) relaxing in the bathtub as Number 5 comes in to show he is still alive.
 * Black Swan has one, but it soon turns into Fan Disservice.

Live-Action TV

 * Alexa Hamilton has a bathtub scene after becoming invisible in the Pilot Movie The Invisible Woman.
 * In the Star Trek Deep Space Nine episode "Crossover", Intendant Kira greets Major Kira as the Intendant is just coming out of her bath, escalating the sexual tension of the scene.
 * The entire shtick of Umeko/DekaPink, rubber duckies and all.
 * An episode of The Sarah Connor Chronicles shows Sarah shaving in the tub, when she accidentally cuts herself. Cue dramatic shot of blood in the water.
 * Used as a Crowning Moment of Heartwarming in the Season 3 premiere of Angel. Seeing Cordy is in pain and distraught over yet another vision, her resident ghost prepares a nice foamy bath and scrubs her back with a loofah.

Webcomics

 * Parodied in the Order of the Stick prequel volume On the Origins of PCs, in which Haley's bath is interrupted and she complains about her Fan Service scene being cut short. Note that this is a Stick Figure Comic (unusually well crafted and expressive stick figures, true, but even so, it requires a rather active imagination to get turned on by them).
 * Supernormal Step gives us a bathtub scene here.