Area Code 33 – Chachoengsao/Chon Buri/Rayong

Overview

The +66 33 area code is a geographic National Destination Code (NDC) assigned to the Eastern Seaboard region of Thailand, covering the provinces of Chachoengsao, Chon Buri, and Rayong. This area is a major industrial and logistics hub, home to key ports such as Laem Chabang and Map Ta Phut, as well as popular tourist destinations like Pattaya and Koh Samet.

Geographic Coverage

The area code serves the following provinces and major cities:

• Chachoengsao: provincial capital Chachoengsao town, plus districts such as Bang Khla and Phanom Sarakham.
• Chon Buri: includes the city of Chon Buri, the resort city of Pattaya, and industrial zones like Si Racha and Laem Chabang.
• Rayong: covers Rayong city, Map Ta Phut industrial estate, and the island of Koh Samet.

These provinces form the Eastern Economic Corridor (EEC), a special economic zone, which has driven significant investment and infrastructure development.

Dialing Formats

When dialing a landline number within Thailand, the trunk prefix 0 is used, followed by the area code (without the leading 0) and the subscriber number. For example, a number in Pattaya might be 0 33 123 456.

From outside Thailand, callers must use the international access code, followed by Thailand's country code +66, then the area code (dropping the leading 0) and the subscriber number. The same number would be dialed as +66 33 123 456.

Local vs. International Calls

For local calls within the same area code, it is often possible to dial just the subscriber number (7-8 digits) without the area code, depending on the local exchange configuration. However, for calls from other provinces or from mobile phones, the full national format (0 33 xxx xxxx) is required.

International callers should note that Thailand's numbering plan is closed, meaning that the area code must always be dialed when calling from abroad. There is no separate 'trunk prefix' for international calls; the +66 replaces the leading 0.

Overlay and Numbering Considerations

As of the latest ITU-T recommendations, there is no overlay code for this geographic area; the 033 code is unique to the region. However, due to the rapid growth of the Eastern Seaboard, the National Broadcasting and Telecommunications Commission (NBTC) may introduce additional area codes or number expansion in the future. Always verify the current dialing procedures with your telecom provider.

Practical Examples

• Calling a landline in Rayong from Bangkok: dial 0 33 456 789.
• Calling the same number from the United States: dial 011 66 33 456 789 (or +66 33 456 789 from a mobile).
• Calling a landline in Chachoengsao from a Thai mobile: dial 0 33 234 567.

Understanding these formats ensures seamless connectivity with businesses and residents in this economically vital region.