There is no visible nudity at all, but some of the main characters do look like they are naked all the time, implying the Moomins.

Some kissing and hugging.

Some love-interests.

Moomintroll is almost like a "player", always getting the women, because he is so cute.

A couple of visible breasts are seen whenever mermaids are present (not sexual).

Cartoonish violence throughout.

A little blood.

Some bruises.

Some violent situations. Especially in a banned episode, where a pirate holds a knife to one of the main characters throat. Moomintroll is also implied to have gotten poisoned.

Little My gets frozen in one episode and in one episode almost dies, because she fell from a kite from a great height.

The series is still very tame and light-hearted.

Nothing explicit. Some very minor profanities.

Only, there was one quite graphic profanity that came out of the Policeman's mouth. It was the S-word, but this happened in a banned episode and it was in Japanese.

There is a lot of alcohol usage. Moominpappa drinks it daily and often talks, or brags about it.

Some pirates drink rum.

Moomintroll and Sniff accidentaly give alcohol to a tortoise. They thought it was "youthful medicine". The tortoise later comments that the medicine made him feel warm and he starts to wander around unorthodoxly.

Some smoking. Moominpappa uses a pipe.

Moominpappa also tells that real sailors spice their tea with rum.

There are many nightmarish creatures throughout.

The Groke is can be extremely intense and scary for kids. Even some adults may find her very creepy-looking.

There are ghosts, goblins, demons, monsters and spirits.

There were some cannibalistic plants that tried to kill and then eat one of the main characters. They can be soothed and controlled by music, but are still quite unsettling for younger viewers.

Lots of weird stuff happening everywhere.

Many strange adventures and dangerous situations are guaranteed!