£97,560 was provided by the Scottish Government's Scottish Green Bus scheme, along with £132,000 from Transport Scotland's Future Transport Low Carbon Vehicle Fund.
When fully charged, the new bus has a range of around 70 miles, and is expected to make five round trips on its 12-mile airport route before returning to base for charging.
A rapid-charger, due to be installed later this summer, is expected to reduce the charge-up period to two-and-a-half hours.
"We were delighted to receive 100% funding support for the electric bus," comments OIC transport manager Laura Cromarty.
"Providing special training in operating the vehicle has been a big part of our preparation over the past month or so," states Orkney area manager for Stagecoach, Stephen Reed.
"The drivers have been enjoying getting to know the vehicle. We're now looking forward to operating it on the route – we think the travelling public will also enjoy the experience."