Formal:
* Obrigado(a) pela maravilhosa férias. (Thank you for the wonderful holiday.) - This is the most formal way to say it.
* Agradeço(a) pelas férias agradáveis. (I thank you for the pleasant holiday.) - This is a more formal and polite way to express gratitude.
Informal:
* Obrigado(a) pelas férias incríveis! (Thank you for the amazing holiday!) - This is a more casual and friendly way to say it.
* Valeu pelas férias top! (Thanks for the awesome holiday!) - This is a very informal way to say it, commonly used among friends.
* Muito obrigado(a) pelas férias! (Thank you very much for the holiday!) - This is a more common way to say it, and it can be used in both formal and informal situations.
Adding a personal touch:
You can also add a personal touch by saying something like:
* Gostei muito das férias. Obrigada(o)! (I really enjoyed the holiday. Thank you!)
* Vou guardar boas lembranças das férias. (I will keep good memories of the holiday.)
* Espero voltar em breve. (I hope to come back soon.)
Remember to replace "obrigado" with "obrigada" if you are female.