The real risks
Road traffic is the biggest one. Thailand has high motorcycle fatality rates; if you rent a scooter, wear a helmet and check your insurance covers it (most do not).
Petty theft is rare but exists in tourist areas. Violent crime against visitors is very uncommon.
Scams worth knowing
The 'temple is closed' scam in Bangkok, tuk-tuk gem shop detours, and jet-ski damage claims in Pattaya and Phuket. All are avoidable: book boats and vehicles through a hotel or operator, and never hand over your passport as a deposit.
If someone approaches you unsolicited near a major attraction with a great deal, walk on.
Health and water
Tap water is not for drinking; bottled water is everywhere. Street food is generally safe where it is busy and freshly cooked.
Dengue exists in the rainy season; mosquito repellent is more useful than panic. Travel insurance with medical evacuation cover is essential, not optional.
