IT goes without saying that much of what an island holiday needs arrives by boat or plane.

The beer, the sunbeds . . . the bloke fixing the air con.

Sunrise at Halkidiki Beach with Mount Athos in the background, Greece.The trick here is that Halkidiki barely feels like the mainland Credit: Alamy

And holidaymakers end up paying the difference.

Holiday comparison site TravelSupermarket has found five island faves where a week away can cost hundreds of pounds per person more than it does on the mainland coast of the same country.

Here, we list that will save you a fortune.

MADEIRA for the ALGARVE – Save £344pp

Panoramic view of Funchal, Madeira, with colorful buildings along the coast and a mountainous backdrop.Madeira is all verdant forests, cliffs and volcanic drama, and it charges for the privilege Credit: Getty Beautiful beach on the Algarve coast, Portugal, with rock formations, a sailboat, and turquoise water.What the Algarve has that competes is the same coastal theatre with sandy beaches Credit: Poike

is all verdant forests, cliffs and volcanic drama, and it charges for the privilege.

What has that competes is the same coastal theatre with sandy beaches.

The Seven Hanging Valleys Trail scrambles along golden cliffs between Praia da Marinha, regularly voted one of Europe’s best beaches.

And don’t miss the Benagil sea cave with its famous skylight.

Base yourself in Lagos for the Ponta da Piedade arches, or Albufeira for waterparks, dolphin-spotting boat trips and a full strip of restaurants.

IBIZA for COSTA BLANCA – Save £336pp

The old town of Ibiza, with its harbor full of boats and buildings illuminated at dusk.Nowhere can match Ibiza’s superclub DC10, but the Costa Blanca gets closer than you would think Credit: Getty Images View of Benidorm, Spain, with palm trees, multi-colored buildings, and people walking along a street.Alicante’s old town, El Barrio, runs tapas crawls into club nights that finish at 3am, and the city has two miles of golden sand at San Juan Credit: Getty

NOWHERE can match superclub DC10, but the Costa Blanca gets closer than you would think.

, runs tapas crawls into club nights that finish at 3am, and the city has two miles of golden sand at San Juan.

Benidorm, half an hour up the road, is a 24-hour operation with cabaret, karaoke and Blue Flag beaches.

For the stunning holiday snaps, there’s the whitewashed coastal towns of Altea as well as Calpe, where the 332m Penon de Ifach rock rears out of the sea.

SKIATHOS for HALKIDIKI – Save £180pp

Skiathos town with white houses on a hill, boats docked in the clear blue water, and a bright blue sky.The picturesque isle of Skiathos Credit: Getty

THE trick here is that Halkidiki barely feels like the mainland.

Sithonia’s pine-backed coves, including the turquoise waters of Kavourotrypes and the fjord-like bay at Porto Koufo, are a match for anything on the isle of Skiathos.

Kassandra has big organised beaches and hotels, with the northern resorts the easiest to reach from airport.

Check out the boat trips that run along the monastery coast of Mount Athos.

MENORCA for COSTA BRAVA – Save £163pp

A secluded beach in Menorca, Spain, with turquoise waters, white sand, and lush green trees on rocky cliffs.Menorca is known for its calas, small sheltered coves where a scoop of sand sits between pine-topped cliffs Credit: Getty Elevated view of Cala Futadera near Tossa del Mar on the Costa Brava in Spain, with numerous boats in the turquoise water and on the beach.The Costa Brava has them too, along the Cami de Ronda Credit: Getty

is known for its calas, small sheltered coves where a scoop of sand sits between pine-topped cliffs.

has them too, along the Cami de Ronda, the old smugglers’ path that links cove after cove.

Aiguablava and Sa Tuna below Begur are the postcard ones, and the clifftop walk between Calella de Palafrugell and Llafranc takes 20 minutes.

Add the medieval walls at Tossa de Mar, the Dali Theatre-Museum at Figueres and tapas in Girona, and there’s more to do on the mainland on less sunny days.

MAJORCA for COSTA DORADA – Save £153pp

View of Palma de Mallorca town, Spain, with the cathedral and beach.Majorca has been a popular family hotspot for decades, with shallow bays, kids’ clubs and waterparks Credit: Getty Illustration of the Coral Bay water park with various water slides and pools, surrounded by palm trees and buildings, with the ocean in the background.The Costa Dorada does the same job for less, and it has PortAventura World Credit: Portaventura Park

has been a popular family hotspot for decades, with shallow bays, kids’ clubs and waterparks.

The Costa Dorada does the same job for less, and it has one thing the island can’t match — PortAventura World.

It boasts everything from the eight-loop Dragon Khan and the 100m-plus drop Hurakan Condor, to Ferrari Land and the Caribe water park.

Plus, Salou has two long sandy beaches and a lively strip, Cambrils next door is the seafood port, or check out Tarragona’s Roman amphitheatre by the sea.