The Thames was once the hub of London life, a vital artery for commercial shipping and for travel. But Londoners have always used the river for recreation: In the 1700s, it would have been dotted with thousands of little pleasure boats and barges. Rivergoers in 1251 might well have seen King Henry III's polar bear, let loose in the Thames near the Tower to fish for its supper. More recently, there have been sightings of seals and dolphins as far upstream as Richmond.

Today, a river cruise remains the most pleasant way to view and to visit many of London's great sights, from the Millennium Dome in the East to Hampton Court Palace in the West. Most cruise services include a good running commentary; you don't have to struggle with London's hot, overcrowded tubes, and the great views are thrown in for free. This brief guide to cruises on the Thames gives you an idea of which services to use and what you can expect to see on your trip.

Central

This is an excellent way of seeing the key river sights of central London -- including the Houses of Parliament and Big Ben, St Paul's Cathedral, the Tower of London, Tower Bridge, the London Eye, the South Bank and County Hall and St Katharine's Dock. If you simply want to sightsee, take a circular cruise. If you intend to visit various attractions along the way, make sure that you take a 'hop-on/hop-off' service, which allows you to get on and off at Westminster Pier, Waterloo Pier, Blackfriars Pier, London Bridge City Pier and the Tower Millennium Pier. Pick up a map from your tour operator showing which piers are best for which sights. Some cruise services offer tickets that include entry into various attractions, which helps to cut down on queuing time. Ask your tour operator for more information about this and other deals when you buy your ticket.

Circular Cruises

From Embankment Pier: all sights from Waterloo to the Tower of London, with multi-lingual commentary. Departures hourly 10.15-17.15; then hourly from 18.30-22.30; £6.70/ £4.70 child; 020 7987 1185.

From Tower Pier: all sights from the Tower to

Westminster. Departures half hourly 11.00-18.00; £5.80/ £3.20 child; 020 7623 1805.

Also: combine your road and river sightseeing with Frog Tours, which offers trips in an amphibious vehicle, specially converted from a WWII landing craft. Departures 10.00, 12.00, 14.00 & 16.00; £13/ £7 child; 020 7928 3132.

Hop on/Hop off

From Westminster Pier: tickets valid all day; stopping at Westminster Pier, Festival South Bank Pier, London Bridge City Pier and St Katharine's Pier.

Until 3 Sept: daily 11.00-19.30, then daily 11.00-18.00; departures approx. every half-hour; £5.80/£3 children; 020 7936 2033.

Also: the River Pass, which allows one day's unlimited travel on all Catamaran Cruiser's sightseeing services, covering most stops between Westminster and Greenwich. £10/£5 children; 020 7987 1185.

For one-way or return services to all piers to the Tower of London or St. Katharine's Docks, simply turn up at either Westminster Pier (Westminster) or Embankment Pier (Embankment), where you will find frequent services. Expect to pay approx £4.80 for a one-way ticket to the Tower and £6 for a return.

Downriver

A river cruise east of the Tower of London takes you past the spectacular glass-and-steel developments at Docklands and Canary Wharf to the rather more picturesque surrounds of Greenwich -- good for visiting the National Maritime Museum, the Old Royal Observatory and the Royal Naval College. From Greenwich, it's just a short hop across the river to the Millennium Dome; you can also go direct to the Dome from central London. A little further downstream is the Thames Barrier, London's flood defence.

The best piers for cruises to Greenwich are Westminster

and Embankment. Cruises depart approximately every half-hour between 10.00-17.50 (cruise time 2 hours return). Expect to pay about £7.60/£3.80 child for a return ticket.

White Horse Fast Ferries offer a very cheap, quick commuter service between Blackfriars, London Bridge, Canary Wharf and Rotherhithe, which costs £1.90/£1 child per stop (0870 240 3240).

The Millennium Express Service, which goes straight to the Dome, leaves from Waterloo and Blackfriars piers and costs £8.40/£5.20 child return, with a cruise time of 1 hour (020 7740 0400).

Upriver

If you have images of idyllic summer days spent picnicking on the banks of the Thames, head West to Kew, Richmond, Twickenham or Hampton Court. Here you'll find weeping willows trailing fronds into the water, pubs selling pitchers of Pimms, swans and ducks idling about and the occasional rowboat sculling past. PG Wodehouse would approve.

From Westminster Pier: to Kew, Richmond, Twickenham and Hampton Court. Departures at 10.15, 10.30, 11.15, 12.00 & 14.00; £14/£7 child return; 020 7930 2062. The cruise time to Hampton Court is 3 1/2 hours. This stretch of the river can be subject to extreme tidal conditions, so call before you travel.

Dinner

Dinner cruises generally include a 4-course meal, wine and entertainment. Most leave from Westminster and go all the way down to the Thames Barrier and back.

The London Showboat Dinner Cruise,

£45 (half-bottle wine), 020 7237 5134

Bateaux London Dinner Cruise, £57 (without wine), 020 7925 2215

The Silver Sturgeon, £55 (without wine),

020 7480 7770

For a more comprehensive guide, pick up a copy of London Transport's Thames River Services brochure at any travel information centre. For river travel information over the phone, call 020 7222 1234.