Aria and Amanchu! are both works of Amano Kozue. The animation is quite similar and both are Slice of Life anime. They share the same calm and relaxing atmosphere and have a female character with a particular passion as the main protagonist. Nature (especially water) and friendship are strong themes in both Aria and Amanchu!.
Just by watching one episode of each show you should be able to tell that same person is author of their source material. These are some of the most relaxing shows which focus on activities relating to water.
Main difference between these shows is their subject where Aria is focused on Gondolas while Amanchu is focused on scuba diving.
Both done by the same author "Amano Kozue".Both Amanchu! and Aria are relaxing,related to water(Amanchu is about diving while Aria is about rowing gondolas), and have the same director.The characters are sure not really similar to each other but there are two girls from Teko's flashback who share the similar VA(and somewhat similar appearence) as Aria's Akari and Aika.
both series are based of a manga by the same artist, they are actually so similar The OST, The characters and the theme of the ocean is shared between the two, If you like relaxing anime give this a try.
Both of these shows are very calm. They have soothing music, beautiful sceneries, and slightly quirky characters. Also, both take place in rather rural areas. Both could be classified as "healing" anime and they're perfect to watch when you just want to unwind and calm down, and the occasional (but more common in Amanchu) silly and goofy gags are sure to put a smile on your face after a long and tiring day.
Both made by J.C Staff, 'Amanchu!' and 'Flying Witch' both have the same overarching lighthearted feel. The 'Slice of Life' genre is explored in both and each of the main characters move to a more rural setting, where they meet new people. The art style is comparable in both: highly detailed, brightly coloured landscapes and similar character designs.
The main differences lie in the two locations: the seaside in 'Amanchu!' and rural Japan in 'Flying Witch'. The former focuses on diving while the latter combines the supernatural with reality.
Both give a similar "relax and smile" vibe. Special to begin the day with a calm mind, escorted by great and relaxing music on these pure Slice of Life calmness.
Away from the city's dizziness and acoustic pollution. Amanchu! is located on the coast while Flying Witch is on the countryside.
Amanchu! is bit more cartoonish.
The greatest aspect of their similarities lies in the light summer theme they share. Refreshing, breezy series revolving around water one way or another with personal relationships at the center; a perfect combination for a relaxing time.
While Tsuritama is a bit on the sci-fi genre with a few supernatural phenomena, they both include a friendship between a socially awkward person and an extremely energetic, albeit difficult to understand at times, one and how they affect each other. Simple comedy that relies on the characters' interactions on an everyday basis and when it comes to it, a story about growing up and discovering your potential. As a bonus, the art of each is very colorful and captures the essence of summer which makes them even easier to watch. read more
New introverted and shy person in school makes friends with a very energetic happy-go-lucky person and there is a wise old lady whose advice helps the characters connect and grow. Socially awkward character + eccentric character friendship is the focus in both shows, both are relaxing to watch and feature a water sport.
Both series primarily follow a few high school girls as they find out more about themselves and grow
(in terms of personality, interpersonal skills and other skills related to their respective passions). Both are lighthearted slice-of-life series with a fair share of introspective moments.
Hikari (nickname: Pikari) (Amanchu!) is very similar to Norie (Tamayura) in that both are very energetic girls who already have a passion in life (deep sea diving and making desserts, respectively). The single-mindedness and focus that Hikari has for diving is perhaps more comparable to the passion that Fuu (Tamayura) exhibits for photography.
Meanwhile, Futaba (nickname: Teko) (Amanchu!) and Maon (Tamayura) are very similar in terms of their shy personalities and introverted nature. Like the main characters in Tamayura, Futaba seems to gain more confidence over time.  read more
Amanchu and Long Riders share a similar scenario/plot and characters. In each our main character is learning something new and trying a new sport/hobby. Amanchu has diving and Long Riders is about cycling, the main character of each show is very new or never tried the new sport and has a friend to teach them everything there is to know while making new friends along the way. If you enjoyed the relaxed slice of life vibe from either show I would recommend the other.
The atmosphere and characters are very similar, and they are both directed by Kenichi Kasai. Hikari and Futaba strongly resemble Akira and Fumi respectively in both appearance and personality. Both shows have a school setting, deal with a club, and have strong yuri vibes. A difference is that Amanchu! has much more comedy.
Fune wo Amu and Amanchu! are very peaceful and relaxing slice of life anime about a group of people working towards their respective goal (Scuba-diving in Amanchu and making a dictionary in Fune wo Amu). If you need to watch something after a very stressful day, then this is for you.
They both have very similar flow-y animation along with the similarity of being by the ocean. Both anime's have cute bubbly characters and a strong friendship vibe. There's also a similar aura/atmosphere between both that's light heart-ed and cute.