Roaming while Cruising

I’m new to Lebara. Just about to embark on a cruise from UK calling at Portugal, Madeira, Canaries and Spain. I joined Lebara to avoid excessive roaming charges I’d incurred with a previous network provider. Do I need to I anything to avoid charges? Most phone usage will be on board via wifi.
Thanks

As lebara doesn't offer credit you cant be overcharged unless you turn on auto top up