Mait Nilson, 44, a mechanical engineer who worked on the project for the past seven years, waved goodbye to friends and fans as he set off from Taillin on a journey he estimates will take nine months.
"This has been my dream since I was a 10-year-old boy and spent summers at our cottage near lake Peipsi in East Estonia," Nilson told AFP before his departure in the vehicle dubbed Amphibear.
Photos on his website www.amphibear.com depict a vehicle that looks much like a typical 4x4, aside from large attachments surrounding it which allow it to metamorphose into a 10 metre boat.
It sports an anchor, hydraulic pump and portable toilet. A stove is built into the back door.
"The first sea crossing will be the Strait of Gibraltar, the first river crossing is in Senegal, and the first ocean crossing is the Atlantic," Nilson told AFP.
He will be joined by several co-pilots on different legs of the journey.
"Amphibear can cover 120 nautical miles in a day in ideal conditions. Most legs last less than 5 days and can be covered when the weather forecast is good. On land the car-boat can drive at speeds of up to 110 km/h," Nilson said.
The vehicle will cover 60,000 kilometres (37,000 miles) through Estonia, Latvia, Lithuania, Poland, Slovakia, Slovenia, Italy, France, Spain, Morocco, Mauritania, Senegal, Cape Verde, Brazil, Argentina, Chile, Peru, Colombia, Panama, Nicaragua, Honduras, Guatemala, Mexico, USA, Canada and Russia.
"So far I have spent around 200 hours at sea with my amphibious car," Nilson added.
"As an amphibious vehicle, Amphibear has some disadvantages when compared to a catamaran or a boat. It has a higher centre of gravity, less room for crew and equipment.
"Its big advantage is low wind drag, meaning less risk to capsize due to wind than sailing catamarans," Nilson said.