It's a slightly vague question as bulgaria is a large country, check out some of the coastal resorts. these beautiful cities on the back sea i.e. bourgas & Varna are offering investors an excellent ROI.

I own a studio near sunny beach & 2 2beds just north of Varna. I'm doing pretty well from it!!

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Investing in Overseas Property go to 4Front or Looking at specific large scale resort communities visit - The Bulgarian Aheloy Beach Residence, Regal Palms, Vista Cay or Cape Verde's Dunas & Tortuga