The riverside is a great location. Most major tourist sites in Bangkok are just a few steps away from the river, and after spending a hot day tramping around temples, the river really cools you off in the evening.
The river is where you will find some of Bangkok's oldest, and posh-est hotels. The grand dame of these is the Mandarin Oriental (also known as just “The Oriental“ to us old-timers). The original building dates from the late 1800s and still retains some of that charm of a bygone era. With its combination of luxury and history, The Oriental makes a great place to start your visit to Thailand.
Sited almost directly across the river from The Oriental is the relative newcomer Peninsula. Offering a similar level of luxury, the hotel's fans believe that the high-rise on the west bank of the river has the better view. Down the river from both of these is more resort-like Anantara Bangkok Riverside. Although it rates five stars, the atmosphere here is much more laid back than either the Peninsula or The Oriental.
Rounding out the top-end are two other relative new-comers, both located up-river from the older hotels. Praya Palazzo is a small boutique style hotel built on the grounds of a century-old mansion. It has the curious distinction of being reachable only by boat. Not far from Praya Palazzo is The Siam. Although newly built, The Siam features a number of elements harking back to the old colonial era, and it's walking distance to the many old palaces and museums of the Dusit area.
Other riverside hotels worth mentioning: