Temporary GST registration

The GST Act defines as casual taxable person as a person who occasionally undertakes transactions involving supply of goods or services or both in the course or furtherance of business, whether as principal, agent or in any other capacity, in a State or a Union territory where he has no fixed place of busines

Your business place will be GOA , where you have to Registered as Casual Taxable Person (in term of Section 27 of CGST Act)