Film:
- Astrid and Hiccup's relationship has continued to grow throughout the film. As was also noted of the previous film, "they're obviously in love without having to be obvious about being in love."
- Astrid and Hiccup get married at the end of the film.
- Throughout this franchise there's always been the underlying assumption that Astrid is totally, hopelessly out of Hiccup's league - indeed, this forms the basis of a Running Gag courtesy of Tuffnut whenever the subject of marriage comes up. But towards the end of the film, when Hiccup is in need of a Rousing Speech, Astrid tells him that she credits him with making her the person she is today. And when you consider that she was once an Ice Queen who was incredibly gung-ho about dragon-slaying, you realize how far she's come for having been the first to understand what Hiccup had achieved with Toothless.
- At a particularly low point in the film (especifically with Hiccup having crossed the Despair Event Horizon), Astrid is asked by Valka if she still believes in Hiccup even after everything that's happened in the film. She answers that she does without even having to think about it. Just before that Valka points out that Hiccup thinks he has to rule alone because his father had to. That Astrid should remind him how strong they are together.
- The baby Night Lights are downright adorable. Their patchwork coloration resembling bicolor/tuxedo kittens adds up to the aww factor.
- The massive, moose-like Crimson Goregutter that befriends Fishlegs' baby Gronckle. And despite his fierce and majestic demeanor, he pretty much becomes a giant playful puppy around his tiny little friend. And woe befall anyone who even dares to threaten the little guy...
- The Berkians greeting the newly rescued dragons with fish and warm sentiments. It really shows how far they've come from the days when they shot dragons down on sight.Viking man: Welcome to paradise, mate!Viking woman: Aren't you a beauty?
- The first of Stoick's flashback scenes has him telling Hiccup about The Hidden World and how it will be Hiccup's job to find it when he's older. Not only is this demonstrating that Stoick always believed Hiccup was destined for great things, but he also expresses that the reason for finding it is so they can end the war between humans and dragons. It's notable that at this point in time, Stoick loathed dragons, believing one to have killed his beloved wife, yet the way he phrases it isn't in a genocidal sense, but so that both races can live in peace away from each other and the harm that either race could inflict on one another. It shows that despite his obsessions in the first film, Stoick never truly wanted to kill dragons, but believed it was the only way at the time.
- Stoick telling little Hiccup that Valka was the only one for him.
- The flashbacks themselves have Stoick being a very gentle, loving father when Hiccup was very young. It's entirely possible that their relationship only got truly strained shortly before the events of the first film.
- Doubling as a Tearjerker, Hiccup and Toothless are understanding for their need to be apart and share a hug before they part ways, with their last moment of physical contact being Hiccup's hand parting from Toothless' snout, the very first gesture that solidified the start of their friendship.
- This scene has extra heartwarming if you've seen Gift of the Night Fury: in that special, Hiccup hugged Toothless when he returned to Berk after a long journey trying to find his helmet. At the time, Toothless was visibly confused as to the meaning of the gesture, as dragons didn't do anything like it, but he understood it was not a hostile action. Here, he actually initiates the hug, showing that he understood what it means and decided to make their last moment together count.
- Hiccup and Toothless' reunion in the epilogue. In particular, how gentle Toothless is with Hiccup's children. Sensing they are nervous around him, he stands still, making sure not to scare them and allows them to touch his snout. It's adorable to see how he quickly he accepts his old friend's family.
- Adding to this, the kids' expressions when they get around to petting Toothless. Once they realize that this huge, frightening creature is actually quite gentle, the girl flashes the most adorable smile, and the boy's jaw literally drops in wonder.
- One of Toothless’ babies playfully grabs the boy’s hand when he tries to reach for it.
- This is a sweet moment because, even though the Berkians will keep the dragons' existence a secret for a long time until humanity is ready for them, seeing the old and new generation Haddocks playing with their dragons shows that the time of peace might be arriving soon.
- When Toothless first sees Hiccup and leaps onto the longboat, his eyes are slitted, and he acts apprehensive. But as soon as Hiccup holds out his hand and looks away while shutting his eyes, the very act that started their friendship all those years ago, Toothless's eyes widen as he recognizes his scent, and he immediately starts playing and licking his old rider and friend.
- That the Light Fury quickly gets a thing for Toothless, not just him for her, is heartwarming in itself. In difference to Toothless, the Light Fury is not the last of her kind, and she knows it, and yet she still takes a quick liking to Toothless, showing she either does not care about species, and/or realized and fell for how unique Toothless' personality was.
- The Light Fury saving Hiccup from falling to his death really highlights how far she's come to trust him, especially given that she had tried to kill him at least twice before. Doubly heartwarming because Hiccup seemed to fully expect her to save Toothless and leave him to his fate. His surprised and relieved expression says it all.
- Another way to look at that moment: In a reflection of Hiccup's first meeting with Toothless, Hiccup frees the Light Fury from the thing binding her (namely, Grimmel's poison muzzle), much like when he had Toothless bound in a net, but opted to free him. Like Toothless, the Light Fury isn't a mindless animal... she is well-aware that Hiccup freed her from Grimmel's control. Like how Toothless didn't kill Hiccup at their first meeting, the Light Fury repays the favor and saves Hiccup from death.
- Drago's Bewilderbeast is briefly glimpsed in the Hidden World, cheerfully roaring along with the rest of the dragons as Toothless stands atop his glowing crystal pedestal with the Light Fury. Having been raised by a cruel master and treated as a war machine all his life, it's rather nice to see him find a second chance to live peacefully in the Hidden World and holds no ill will against Toothless who had defeated him and destroyed one of his tusks in the previous film.
- When Toothless flies with his new tail for the first time, the look he gives Hiccup from the sky is pure "Lookit me, daddy!"
- During the scene of Hiccup and Astrid's wedding, they were married in front of a huge statue of Hiccup's father Stoick in New Berk, with all of their friends, family members and everyone of the Hooligan Tribe in attendance. The entire village honoured Stoick enough as their previous chieftain to build a memorial statue of him, which shows how much they placed Stoick's memory in high regard.
- If you look carefully, before Gothi wraps their hands, you can see in the background, on the statue of Stoick, Toothless is carved into it and the way that it's done, it's as if the dragon is looking right at Hiccup as he gets married, heartwarming and a tearjerker at the same time.
- Look carefully at the medallions the couple are wearing. They have pictures of their dragons on them.
- Eret catching the bouquet.
- Tuffnut and Ruffnut comforting Snoutlout and Fishlegs is both this and Funny.
- Small moment but when Ruffnut was let out of her cage after annoying the hell out of Grimmel, he gives her a baby dragon, she slowly reaches out and pets the little creature. While it is standard for getting a dragon to trust you, it's still a nice gentle gesture from Ruffnut of all people. And she expresses disgust when she hears that he feeds baby dragons to his dragons.
