If you've got that friend or family member who keeps talking about going on a cruise but can't quite commit, a cruise line gift certificate might be the perfect holiday gift.

These plastic or electronic certificates can be redeemed towards cruise fares or extras, such as spa treatments, shore excursions, or even drinks. Your grateful pal may think of you when he or she enjoys frosty piña coladas and ocean views on the pool deck in the sunny Caribbean.

Note: If you are planning to buy a plastic gift card, do it ASAP to assure it arrives in time for the holidays. Your travel agent may also have some available for sale.

How It Works

Each cruise line has its own rules for what you can and cannot use the credit for. For example, with Royal Caribbean, you can't use it towards gratuities, nor in the casino, but other lines don't have these restrictions. Your best bet is to read up on the card you're eyeing and make sure you understand the fine print before you make a purchase.

You have a choice, typically, of cashing in the card to cover some of your cruise fare when you book, or you can use it to add dollars to your onboard spending account. When you can do that varies: With Norwegian, for instance, you can redeem the certificate when you check-in at the pier, for Royal Caribbean you need to do it before your cruise.

Here are some top cruise lines and what they offer:

Carnival Cruise Lines sells both e-cards and gift cards online. The plastic cards are also available at some 9,000 retail locations, including Kroger, Giant Eagle, Price Chopper, Safeway, Lowe's, and Office Max. The value available is $100 up to $1,000.

Royal Caribbean gift certificates come in increments of $50, $100, $250, $500, $1,000, $1,500, $1,700, and $2,000 and are available online. The certificates can be redeemed with the cruise line or through your travel agent.

Gift cards and e-gift cards sold by Princess Cruises come in standard denominations from $50 to $2,000. A shipping fee of $1.99 is charged for the plastic cards with a value of less than $100.

Norwegian Cruise Line's gift card is available in denominations of $25, $50, $100, $250, and $500. If you're a holiday-shopping procrastinator, expedited shipping is available for a fee.

A $100 gift card might buy you ten fancy cocktails or twenty beers; it might get you a few professional photos from your trip; or you could use the card to purchase a little bauble at the ship's gift shop, put it towards a massage at the spa, or on dinner at a specialty restaurant.

Occasionally the lines run promotions where there are discount incentives for buying gift cards. There are no deals currently, but check the links above periodically; when there are, this is where they'll post them.