It is highly advisable to have a motorcycle license (Euro) or a motorcycle endorsement on your license (US) before renting a motorbike from us or anyone else. This is something that the police are really looking for lately at their checkpoints. Mostly they are fining people for not wearing a helmet, but you will often also be asked for your license as well and they will look to see if it authorizes you to operate a motorcycle. That said, the checkpoints are pretty much limited to the busy areas of town and only until about 4pm.
Many places in town will rent you a bike and never ask about your license, as they simply do not care if you have a legal problem. They just want their money. We prefer to be a lot more honest about the realities of riding in Thailand. If you are driving daily in the busy areas of town (anywhere near or around the moat), be prepared to be pulled over. The ticket cost is negligible compared to tickets at home… just 400 baht usually… but it’s better to just avoid the area during the day or better yet, get properly licensed before coming.