- Most heartwarming moments in the series are provoked by Yotsuba's wide-eyed gasp of astonishment at some new, mundane discovery.
- Any chapter and moment that simply comprises Yotsuba spending time with her dad, and any time where it's evident how much they love each other and get along like any other father and his daughter.
- In Chapter 5, when Yotsuba and Koiwai are out shopping and Koiwai finds her sleeping in a bed with nearby customers laughing and fawning over her. Doubles as a Funny Moment.
- In Chapter 7 when Koiwai talks about Yotsuba with Fuuka:
Koiwai: She'll be fine. She can find happiness in anything. Nothing in this world can get her down. Nothing.
- Chapter 11 has a minor moment when Yotsuba pulls up the blanket to cover Koiwai while he's sleeping on the futon after doing an all-nighter to do work.
- Chapter 16
- Yotsuba is expecting a souvenir from Asagi even though she simply went on a casual outing rather than a trip. When Asagi returns she simply smiles at Yotsuba and says "Huh?" when the latter asks for her gift. It dawns on Yotsuba that Asagi forgot, and she sadly starts walking away... only for Asagi to call out to her and bring out some fireworks to share with everyone. It shows that not only she didn't forget her promise, but she chose a pretty good present too, even though she didn't have to.
- When her mum asks about it, Asagi says she got them for her because Yotsuba gave her a four leaf clover in the previous chapter, and the fireworks are her way of saying thanks. This is even though the four leaf clover was initially given to her as thanks for her previous souvenir to Yotsuba.
- Chapter 18:
- Yotsuba is going around handing out flowers to random people. She gives one to a police woman, telling her to do her best. Right before the scene shifts, we see a panel of the police woman saying "I will do my best." with a smile on her face. Just goes to show how one act of kindness can make anyone's day better.
- One old man, who pretends he just came back from the dead, tells Yotsuba that heaven is filled with flowers and good food. Yotsuba then goes home to see her father cooking her favorite meal next to several big bouquets, and says "Heaven."
- The small moment of Yotsuba fearhugging her dad after being frightened by the owl in Chapter 19. If you don't wish you could be in Koiwai's place at that point so you could comfort her (even though he looks a bit confused), you have no heart.
- In Chapter 21, Yotsuba learns how awesome fireworks shows are. They even printed a two-page panel of the fireworks IN COLOR!
- In Chapter 27 when Asagi shows Yotsuba what tsukutsukuboshi really are.
- In Chapter 29, Yotsuba helps do chores for the Ayase family. Fuuka carrying a sleeping Yotsuba afterward to a futon for her to rest in tops it off.
- In Chapter 31: "Earth is best after all, right?"
- In Chapter 34 there's the journey home from a day at the beach, with everyone falling asleep on the train.
- In Chapter 40, Yotsuba attempts to follow and find Fuuka at her school - and succeeds. All so she can give her the expensive milk she promised her in the previous chapter. Fuuka is touched (but mostly shocked and impressed).
Fuuka: Th-thank you. You're incredible Yotsuba-chan..
- In Chapter 54 when Yotsuba's spinning the acorns and her dad just smiles at her.
- In Chapter 64 when Yotsuba finally successfully makes her first pancake after failing for so long. Also, beforehand Koiwai encourages her the whole time by making more pancake mix and saying he'll eat all the trial ones because he's Pancake-Loving Man, and Yanda even stops his usual Jerk Ass comments after he accidentally makes her cry.
- Chapter 65 has nothing particularly flashy happening, but Jumbo visits to watch Yotsuba while her dad finishes working; Jumbo brings her a book on animals after looking through Tora's pictures of the recent hot air balloon event, and he sits with her as she discovers the stickers in the book and eagerly puts together her own zoo; Yotsuba starts to get tired, but stays awake because she wants to play with her dad and Jumbo, and it's just such an accurate depiction of a kid that age that it can't help but be endearing; Dad decides it's time for bed, and Jumbo has to agree to come back tomorrow so they can all play then.
- Chapter 66 has Yotsuba holding hands with her dad and Jumbo while they walk through the parking lot of the electronics store. She counts off and they both swing her by her hands. It really affirms Yotsuba's view of Jumbo as part of the family and seeing her hold hands with her dad and Jumbo is just so cute.
- Chapter 68
Dad: I don't care that you broke the teacup. Or that you broke the window. Or that you spilled coffee. That doesn't matter.Yotsuba: ...Even if I break another plate?Dad: That's fine. It's your job to screw up.Yotsuba: Even if I break your computer?Dad: Let's... not get too carried away. But... don't lie. Okay?Yotsuba: Okay. I won't lie anymore.
- Yotsuba lies about breaking a teacup. Her dad then proceeds to scare her into telling the truth by taking her to a graveyard. After that happens though, he picks her up and this exchange follows:
- He then proceeds to play the same game with her that caused the cup to get broken.
- In Chapter 72, Yanda starts treating Yotsuba better by letting her play with his bubbles. A little better.
- Chapter 76 has Asagi fixing Duralumin's voicebox while Yotsuba is going through a Heroic B.S.O.D., and her dad and friends attempt to cheer her up in the meantime. Even Yanda, in his own way (aka provoking her, though he does try to make her laugh too).
- Chapter 77 has Torako (unintentionally) spending time with Yotsuba while waiting for Asagi to come home, and she decides to teach her how to tie a bow. During the whole time she's with her, Tora actually nearly breaks into Not So Stoic quite a few times; in particular, when Yotsuba finally succeeds in making a bow, Tora's facial expression is closest to a smile readers have gotten from her at this point.
- In Chapter 79, when helping Yotsuba clean off the paint from the previous chapternote , Koiwai decides to leave the last footprint alone. When Yostuba asks why, he says he wants to keep it as a memento.
- Chapter 81:
- Yotsuba is excited about going on a camping trip, until she finds out that Yanda is going with them. She's being very grumpy on the drive over, so Yanda has the other girls draw on his face to make her laugh.
- Yotsuba calling for Koiwai at night from her tent because she feels lonely and can't go to sleep without him even though Ena and Miura are also with her. Koiwai, who was going to share a drink with Jumbo and Yanda, doesn't hesitate to come in and pat her to sleep like he does at home. The next morning he can actually be seen sleeping next to her.
- In Chapter 85, Yotsuba wakes up late at night and is concerned when she sees that her dad isn't asleep next to her. She walks around the house in the dark looking for him even though she's scared of the monsters. When she finally finds him in his work room, he lets her sit and fall asleep in his lap.
- Chapter 86:
- Yotsuba being super excited to see Grandma; she decorates her home, lists all these things she wants to do with her and impatiently looks for her at the station. When Grandma does come, Yotsuba is incredibly ecstatic - and, typical grandmother-y scolds aside, Grandma is also evidently happy to see her grandchild and is touched when she comes home to the decoration.
- Grandma has a Troll moment when she pretends she didn't bring a present for Yotsuba, then says it was a trap and gives her pears as her present, which just sends Yotsuba into a further tantrum. Then Grandma gives her the actual presents - coloured pencils and a sharpener.
- Chapter 87, where Yotsuba realizes that the sweeping sounds she heard every morning at her grandmother's house was from her grandma sweeping the curb. She really loves her Grandma.
- Chapter 93, "Yotsuba and Princesses", has Yotsuba pretend to be a princess for a day. When she goes over to Asagi's house she even gets a makeshift dress to wear, and dances with her father at the very end.
Heartwarming / Yotsuba&!
You are required by law to grin in delight at least once per chapter. To make a full list, you could easily say "Start with episode one; continue." One could argue that the series doesn't qualify for a Crowning Moment of Heartwarming because there's really no crowning moment — the whole thing is just so dang heartwarming.