There’s a chance of your father being a Portuguese citizen. It would be necessary to check with his full name, date of birth, and name of his parents if he has citizenship. You can either obtain your Portuguese citizenship through your father or grandfather, but through your father is easier.
Can I apply for Portuguese citizenship if my grandfather was registered in Portugal Civil Registry?
My grandfather was born in Macau and was registered in Portugal Civil Registry. My father was born in Hong Kong and was registered in the Portuguese Consulate of Shanghai. Is my father considered a Portuguese national and am I entitled to apply for Portuguese citizenship through my father?
In theory, you can, but it would be necessary to have a look at the Portuguese documents to better understand the situation. It is not possible to give you a proper answer without looking at the documents you have from your father and grandfather.
In principle, yes. Based on the information supplied, you can apply for Portuguese citizenship. However, this needs to be confirmed through a detailed verification of all documentation, yours, your father’s and your grandfather’s.
As you are a direct descendant from a Portuguese citizen, you are in title to apply for Portuguese citizenship, provided your grandfather never had his Portuguese citizenship revoked. This application can be achieved by declaring your intention on becoming a Portuguese national at any Portuguese Consulate or before the Main Office of the Portuguese Civil Registry, providing proof of your relationship with your Portuguese ascendant and also of your links to the Portuguese community.