You have to pay a road toll to use the sub-sea tunnels. The road toll is to be paid online on tunnil.fo
The prices stated for the Vágatunnel and Norðoyatunnel are for a return trip. You are only charged when driving from Vágar through the Vágatunnel, and driving from Klaksvík through the Norðoyatunnel. However, please notice, when driving through the Eysturoyartunnel you will be charged both ways.