How do I say good night father in welsh?

The most common and natural way to say "good night father" in Welsh is:

Nos da, Dad

* Nos da means "good night".

* Dad means "father" or "dad".

You can also use:

Nos da, Tad

* Tad is a more formal way of saying "father".

Other options:

* Hunan da, Tad - This translates literally to "Good night, father".

* Cwsg yn dawel, Tad - This means "Sleep well, father".

The choice of phrase depends on the context and your relationship with your father. "Nos da, Dad" is the most common and natural choice for most situations.