Taxi to Blue Caves from Zakynthos

We are on Azura visiting Zakynthos next month with our granddaughters, they would like to visit the Blue Caves and shipwreck beach but the ship tour is sold out. There are lots of independents operating the tour from Skinari but that seems quite a distance from Zakynthos town where I expect we will dock, does anyone know if we can get a taxi and what sort of cost we should expect.