Travelers planning vacations are discovering that more and more hotels are tacking on resort fees to cover the cost of "extra" services, such as Internet access and fitness center use.

In Hawai'i, the fees seem to turn up more at higher-end resorts on the Neighbor Islands than at hotels on O'ahu. The mandatory daily "resort fees" are added to the bill upon checkout and range from less than $10 to about $25 a day at Hawai'i resorts.

To avoid sticker shock at checkout, most of the hotels and resorts warn guests when they make reservations and when they check in.

Starwood Hotels & Resorts Hawaii's spokeswoman Candice Kraughto said guests who know what they will have to pay and what they will get aren't likely to complain.

"With a resort fee, hotel guests know the resort won't nickel and dime you for special amenities, services or guest activities such Internet, shuttles, fitness center and parking," she said.

Starwood's Hawai'i properties include: The Royal Hawaiian, Sheraton Waikiki, Moana Surfrider, Sheraton Princess Kaiulani and W Hotel Diamond Head on O'ahu; the Westin Maui Resort & Spa, Westin Ka'anapali and Sheraton Maui Resort on Maui; the Princeville Resort, Westin Princeville Ocean Resort Villas and Sheraton Kaua'i Resort on Kaua'i; and the Sheraton Keauhou Bay Resort & Spa on the Big Island.

Yet only three of them charge a resort fee: The Westin Maui Resort, Sheraton Maui Resort and the Sheraton Kaua'i Resort.

"Generally, if they are already informed about the fee, guests are comfortable with paying for it," Kraughto said.

The Sheraton Maui charges $20 a day, which includes a wide variety of services that other hotels often charge per item for, such as yoga or pilates classes, Internet access and children's activities.

The fee includes unlimited use of high-speed Internet in guest rooms; free wireless Internet access in public areas, including the lobby and pool bar; first-night valet parking and daily self parking thereafter; unlimited local (on-island) telephone calls; Starwood Maui scheduled shuttle service to Westin Maui Resort and Spa, Westin Ka'anapali Ocean Resort Villas, and historic Lahaina town; Ka'anapali Resort scheduled shuttle service to Ka'anapali resort and hotels, and The Fairway shops at Ka'anapali; yoga and pilates classes; unlimited use of the fitness center, daily cultural activities, lessons and entertainment; and children under 12 eat free from Keiki Menu at Keka'a Terrace with paying adult.

By way of comparison, the Sheraton Waikiki doesn't charge a resort fee but does charge a $25 daily parking fee.

A Hawai'i-based Web site and travel sales company, www.Travel-Hawaii.com, last year started a database that tracked such fees and listed 16 properties, although one — The Lodge at Moloka'i Ranch — has closed since then.

Travel Hawaii owner John Lindelow said the information on the fees is designed to arm travelers with better information. "Here at Travel Hawaii, we're not big fans of resort fees because we want to be able to sell our clients fully prepaid Hawai'i hotel stays," he said.

"Finding out at checkout that a hotel charges a hefty resort fee could certainly irk some travelers," he said. "On the other hand, many resort fees appear to provide great value — as long as what they provide is something you'd normally use."

Just one of the ResortQuest Hawaii properties charges the fee, according to president and CEO Kelvin Bloom — the ResortQuest Kauai Beach at Makaiwa on Kaua'i.

The $12 fee includes: daily parking (self and valet), unlimited toll-free and local calls, daily use of exercise facility, 15 percent off selected spa treatments, incoming/outgoing domestic faxes from the front desk, coffee or hot tea coupon from the hotel's coffee kiosk, in-room high-speed Internet access, use of in-room safe, coffee packs in-room, daily newspaper, rollaway extra bedding, and kids 12 and under eat free at the Voyager Grille.

He said guests see the fee as a good value, and "as a result, the complaints received have been negligible."

Why not raise rates instead of charging a mandatory fee? Bloom said that's a response to guests who "have told us they prefer to pay a single discounted fee as opposed to being charged for each of these services during their stay."