[ChamametchiandMametchi]

Does it mean that it celebrates Christmas? If so, what happens at Christmas Eve? Does Santa appear at all?

[binary]

Yes, there will be an animation of him appearing, at midnight as Christmas eve turns into Christmas day. You may see him leave a present for your Tamagotchi character, but it's just an animation; there won't be any present there when she wakes up in the morning.

[ChamametchiandMametchi]

Ah. Then I "might" (meaning I might be asleep) see my Tamagotchi get a present.

[MusicalAngelgotchiOfLove]

You could change the date and time a minute early to Christmas day.
Then you'll be able to watch it and afterwards, change it back to it's normal time and date.

[Owl]

You could change the date and time a minute early to Christmas day.
Then you'll be able to watch it and afterwards, change it back to it's normal time and date.

You could... but it's never quite as magical that way.

[Jokus]

Hey, it isn't midnight when santa appears, it's 10:30pm

[Amat Gotchi]

Hey, it isn't midnight when santa appears, it's 10:30pm

Yep, the older connections at least will have Santa come on Christmas Eve at 10:30 PM and bring the Tamagotchi a present. The Tamagotchi never gets to keep the present unfortunately.
If y'all are really keen on ruining the Christmas surprise, set the time to 10:29 PM Christmas Eve.
It's cute when the Tamas celebrate holidays, though. The most hilarious one is Easter. A giant egg that hatches...enough said.