Formal:
* Croeso: This is the most common and general way to say "welcome". It can be used in any situation where you want to be polite.
Informal:
* Croeso i chi: This is a more personal way of saying "welcome" and literally means "welcome to you".
* Croeso cynnes: This means "warm welcome" and is often used in a more friendly or welcoming environment.
For a specific occasion:
* Croeso i'r briodas: This means "welcome to the wedding".
* Croeso i'r parti: This means "welcome to the party".
Note: In Welsh, the "w" in "croeso" is silent. It is pronounced "kro-eh-so".