Shore excursions are designed to help you make the most of your limited time in port by transporting you to sites of historical or cultural value, or of natural or artistic beauty. The tours are usually booked online in advance or on the first or second day of your cruise; are sold on a first-come, first-served basis; and are nonrefundable. Some lines -- but not many -- include shore excursions in their cruise fares.

Generally, shore excursions that take you beyond the port area are the ones most worth taking. You'll get professional commentary and avoid hassles with local transportation. In ports where the attractions are within walking distance of the pier, you may be best off touring on your own. In other cases, it may be more enjoyable to take a taxi to an attraction and skip the crowded bus tours; many lines offer private cars and vans for those who want to tour solo (or you can walk into the port and find a taxi, probably cheaper, on your own).

A few tips on choosing the best shore excursion for you, as you look through your cruise line's shore excursion information: See if the description includes sites of interest to you. Check the activity level of the tour: a "level 1" or "moderate" tour means minimal walking; a "level 3" or "strenuous" marker means you may be climbing steep steps or walking long distances -- especially true in Greece, as some tours of sites and ruins require a lot of walking up steps or over uneven ground. And check the tour's length and price tag -- the longer and/or more expensive the tour, in general, the more comprehensive it tends to be.

When touring in Greece, remember to wear comfortable walking shoes and bring a hat, sunscreen, and bottled water to combat the effects of the hot sun. Most lines offer bottled water for a fee as you disembark.

Also, keep in mind that some churches and other religious sites require modest attire, which means shoulders and knees should be covered.

Cruise lines tend to set shore excursion pricing and options closer to the sail date. We've included 2011 prices to give you a general idea of how much each tour will cost. Shore excursions are a revenue-generating area for the cruise lines, and the tours may be heavily promoted aboard the ship. They aren't always offered at bargain prices.

Below are selected shore excursion offerings at the major cruise ports. Keep in mind that not all the tours will be offered by every line, and prices will vary. The tour may also show up on different lines with a few variations and a different name. 

Corfu (Kerkira)

The Achilleion & Paelokastritsa (4 1/2 hr., $64): Visit the hilltop town of Paleokastritsa on the western side of Corfu, punctuated with olive, lemon, and cypress trees and bays and coves. Stop at the 13th-century Monastery of the Virgin Mary, on the edge of a promontory as well as Achilleion Palace, built in the late 19th century as the home of Empress Elizabeth of Austria. The palace, now owned by the Greek government, has been renovated and guests can visit the home and the gardens, which boast views of the island. The tour includes time for shopping in old Corfu Town before heading back to the ship.

Mountain Bike Expedition (4 hr., $149): Travel from the port by coach to the town of Dassia, where you'll pick up your bike. The bike tour starts with an uphill ride to Kato Korakiana, where you'll stop at a coffee shop. Bike through a narrow, paved alley to get to the town of St. Marcos, with stone houses and a Byzantine chapel. Stop here for a Greek snack and then bike downhill.

Iraklion & Ayios Nikolaos (Crete)

Knossos & the Minotaur (3 hr., $75): Knossos was once the center of the prehistoric Minoan civilization; it is thought to be the basis for the mythological Minotaur's labyrinth. Today it is one of the great archaeological sites. What remains are portions of two major palaces, plus several restorations made between 2000 B.C. and 1250 B.C.; parts of the palace were rebuilt in the 20th century. Visit the excavation of the palace of King Minos; view the royal quarter, the throne room, and the queen's quarters, with its dolphin frescoes above the door. Other sites include the house of the high priest and the "small palace." Some tours include a visit to the archaeological museum, which includes artifacts from the Minoan civilization, or a stop in the town of Iraklion.

Windmills & Lassithi Plateau (4 1/2 hr., $79): This tour takes participants up Mount Dikti to the Lassithi plateau. On the way you'll stop at the monastery of Kera, which houses Byzantine-era icons. The plateau boasts views of nearby mountains and the sailclothed windmills that irrigate the land. The tour includes about 2 hours of walking and standing, and there's considerable climbing involved. The tour includes a stop at a local restaurant.

Itea (Delphi)

The Mythology of Delphi (4 hr., $79): Delphi was the ancient home of the Oracle, where pilgrims came to ask questions of the Greek god Apollo. Visit the Sanctuary of Apollo to see the Temple of Apollo, where one of three Pythian priestesses gave voice to Apollo's oracles; the well-preserved amphitheater; and the Castalian Spring and the Sacred Way. Be sure to visit the museum as well. The tour includes time to shop in the village of Delphi.

Katakolon (Olympia)

Ancient Olympia & Archaeological Museum (3 hr., $74): Visit the site of the original Olympic Games, held from 776 B.C. to A.D. 393 (and most recently used in the 2004 Olympics). View temples and altars, including the Temple of Zeus, which once housed the gold-and-ivory statue of Zeus that was one of the Seven Wonders of the Ancient World; and the original stadium, which could seat 20,000. Also included is the temple of Hera, the shrine of Pelops, the Treasuries, the gymnasium, and the Council House, where athletes took the Olympic Oath. You'll spend about an hour in the museum, viewing artifacts and sculpture and conclude the tour with a visit to the village of Olympia. Some tours feature a folkloric show or snacks in Katakolon.

Mykonos & Delos

A Visit to Delos (4 hr., $65): Delos is the uninhabited island just off the coast of Mykonos where, according to mythology, the gods Apollo and Artemis were born. The island was a religious center. Excavations have uncovered the city of Delos, and the tour explores the site, which includes marble lions, three temples dedicated to Apollo, the theater district, and the Sacred Lake, which dried up in 1926.

Historic Walking Tour of Mykonos (2 1/2 hr., $55): A downhill walking tour of Mykonos town takes in the Archaeological Museum, the Maritime Museum, and Lena's Traditional House, which re-creates the home of a 19th-century Mykonos family.

Nafplion

Mycenae & Palamidi Castle (4 hr., $99): The area is rich with the remains of the ancient Mycenaean civilization. Drive by the ancient sites of Tiryns and come to the ruins of the ancient city of Mycenae, where excavation work begun in the 19th century eventually exposed the Lions Gate, the entrance to the city. Visit the Beehive Tomb, which gets its name from its shape. Take a shopping break at Fithia Village, then return to Nafplion and to the Palamidi Castle, which was built as a fortress by the Turks and Venetians (and later used as a prison). The castle offers views of the Argolic Gulf. Note: The path up consists of nearly 1,000 steps (buses can drive up to the gate).

Patmos

St. John's Monastery & Cave of the Revelation (3 hr., $54): Depart the Port of Scala and travel by bus to the village of Chora and the 900-year-old, fortresslike Monastery of St. John, which overlooks the main harbor and is enclosed by fortified walls. You'll see the main church and the ecclesiastical treasures in the church and museum, including Byzantine icons, 6th-century Gospels, and frescoes in the chapel. Continue on by bus to the Cave of the Apocalypse. Niches in the wall mark the stone pillow and ledge used as a desk by St. John, said to have written the Book of Revelations here; a crack in the wall was said to have been made by the Voice of God. Refreshments are served in Scala. Visitors to the monastery must cover their shoulders; shorts are not allowed.

Pireaus/Athens

Athens & Cape Sounion (8 hr., $132): This tour visits the Acropolis, Athens's most prominent historical and architectural site, in the morning; after lunch, the tour continues to Cape Sounion (about a 1 1/2-2 hr. drive from Athens), the most southern tip of the European landmass. Participants can explore the Temple of Poseidon, which is located at the top of a 60m (200-ft.) cliff and offers a panoramic view of the Saronic Gulf and the Cyclades.

Ancient Corinth and Canal Cruise (7 hr., $90): Drive past the coves of the Saronic Gulf to Isthmia, where you'll transit the Corinth Canal, a slim (30m/90-ft.-wide) waterway blasted through sheer rock in the 19th century. After cruise, explore ancient Corinth. Including the Apollo Temple, Fountain of Glauke, Spring of Periander and the remains of 25-ft wide Lechaion Road. Lunch is included in the tour.

Rhodes

Filerimos Local Mezes & Wine Outing (3 3/4 hr., $63): Participants get a look at Rhodes Town before being driven to Filerimos, where hills are dotted with cypress, oaks, and pines. Visit Moni Filerimou and Lady of Filerimos, an Italian reconstruction of the Knights of St. John's 14th-century church, and ruins of the Temple of Athena. The tour continues to Kalithea Resort, where the thermal water was, according to story, once recommended by Hippocrates for its healing qualities; today the springs have dried up, but the area is known for swimming and scenery. There will be some time for shopping in Kalithea before you stop by a seaside taverna for local food and wine.

Walking Tour of Historic Rhodes (3 1/2 hr., $52): Rhodes, which boasts one of the oldest inhabited medieval towns in Europe, is a great city for walking. This tour takes guests through the Old Town. You'll see churches, the Jewish quarter, the Inns of the Knights, and other spots; you'll tour the rebuilt Palace of the Grand Masters and the Hospital of the Knights, now a museum. And you'll walk down the cobblestoned Street of the Knights, an old pathway leading from the Acropolis of Rhodes down to the port and lined with medieval towers and architecturally interesting facades.

Santorini (Thira)

Village of Oia & Santorini Island (3 1/2 hr., $72): Another whitewashed hilltop town is Oia, the town where so many postcard-perfect photos are taken of blue-domed, whitewashed buildings and the blue sea beyond. There are small cobblestone streets to explore; pop in at shops and cafes. A wine tasting is offered to tourgoers, as well as a walk to the cable car station at the top of Fira.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.