Very different, and they are on opposite sides of Crete too.
Malia is known for hosting young Brits that get wasted and do anything imaginable on the street. I haven't been there so I can't give you much information. Malia is close to Heraklion, the biggest city in Crete.
Chania is a more quiet town, from a party point of view. It has a very beautiful and well preserved Old Town. Also, if you are interested in going to the good beaches in Crete, Chania is where you should be. You will still need to take 1-2 hour car trips for the famous good ones, but you will be on the right side of the island. Platanias is a village near Chania where many Scandinavians go. Families but also groups of young people. The nightlife in Chania itself is not bad, there are clubs and nice bars. The city attracts a lot of domestic tourism but you will find foreigners as well. It's just more "proper", not getting naked in the middle of the street and such.
Malia is known for hosting young Brits that get wasted and do anything imaginable on the street. I haven't been there so I can't give you much information. Malia is close to Heraklion, the biggest city in Crete.
Chania is a more quiet town, from a party point of view. It has a very beautiful and well preserved Old Town. Also, if you are interested in going to the good beaches in Crete, Chania is where you should be. You will still need to take 1-2 hour car trips for the famous good ones, but you will be on the right side of the island. Platanias is a village near Chania where many Scandinavians go. Families but also groups of young people. The nightlife in Chania itself is not bad, there are clubs and nice bars. The city attracts a lot of domestic tourism but you will find foreigners as well. It's just more "proper", not getting naked in the middle of the street and such.
If it won't matter in 30 years, it doesn't matter now.
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