Venice is sure to delight your kids, but if you're worried they'll get tired of plying the canals in vaporetti, try staying at the Lido. It has well-equipped beaches and plenty of games and activities, and if you're touring with a car, it's the only part of Venice you can drive to. Here are some lodgings on the Lido island.
Castro Marina, on the southeastern coast of Apulia, is actually a fairly elegant resort, with plenty of good seafood restaurants in the fishing harbor. What makes this a great kids' attraction is the Grotta Zinzulusa, a huge cave featuring a saltwater lake and a freshwater lake, as well as countless stalagmites and stalactites. Near the ticket office are a good restaurant and a swimming pool; take a 30-minute boat ride from here to the Grotta Romanelli, where you can see the oldest cave paintings ever found in Italy. The Grotta Zinzulusa is open daily 10-1 and 2-6 in winter and 10-6 in summer. Tel. 836/97326. Here are some accommodations. http://www.excellenthotels.com/go/hotels/italy/san-remo/
More beaches that are suitable for children are:
San Remo has long breakwaters that create small natural pools. There are loads of organized kids' activities, and there are babysitters so Mom and Dad can hit the elegant casino after dinner! Here are some accommodations.
Lerici is in the calmest part of huge La Spezia Bay. You'll find lots of safe beaches, attractions and games, and you can take a nice side trip to see the fairy tale sanctuary dedicated to St. Peter: it looks like it was built for King Arthur. Our favorite hotel is right on the beach, and has rooms for families with 2 or 3 kids.
Viareggio to Forte dei Marmi is virtually one long stretch of wide sandy beaches with a gently sloping sea floor and lots of games for kids. Villa Riviera Toscana is a family-friendly mansion with a gated garden where the kids can safely play while parents take a nap.
Lake Garda . Italy's hundreds of lakes are great places for safe family swimming. We picked Garda because of nearby Gardaland, an American-style amusement park with water slides, rides and other attractions. It's located in Peschiera del Garda, open daily from March-Sept., and it has an authentically American-style resort hotel right next door. If you're looking for more Italian-style lodgings, here is our favorite choice.