Ako Bikolano/Bikolana
This translates directly to "I am Bicolano/Bikolana." "Bikolano" is used for males, and "Bikolana" is used for females.
You could also say:
* Taga ako sa Bicol (I am from Bicol)
* Ako tawo kan Bicol (I am a person from Bicol)
These options emphasize your origin rather than your ethnicity.