There are a few local Bike Rentals in Pomorie.

Non of them really have websites or anything like a reservation system but we suggest walking past early enough in your stay so that you can check prices and availability. Prices are around 15-20 BGN per day.

Non local

If you want high quality bikes Motoroads.com offers a wide range of bicycles for rent for multiple days: city, hybrid, mountain bikes, touring, racing, ladies, electric and bicycles for kids. They also offer professional bike gear, accessories and equipment for rent. Their prices are reasonable for new bikes and low rental rates available for used bikes. You will need to reserve in advance.

To find more information please follow the link below.
Multi day Bicycle Hire Pomorie