Do I need an appointment to extend my 30-day arrival visa in Thailand by 2 weeks?

You can typically extend a 30-day arrival visa in Thailand by 14 days for the usual fee without needing an appointment. However, it's recommended to go early in the morning to avoid long queues, as the process is handled on a first-come, first-served basis. Make sure to check the local regulations or specific requirements at the immigration office where you plan to apply, as practices can vary.