Area Code 405 – Kolaka

Overview of Area Code +62 405

Area code 405 is a geographic National Destination Code (NDC) assigned to the Kolaka Regency (Kabupaten Kolaka) in the province of Southeast Sulawesi (Sulawesi Tenggara), Indonesia. This code follows the ITU-T E.164 international numbering plan, where the full international dialing format is +62 405 xxx xxxx. Domestically, callers within Indonesia dial 0405 xxx xxxx (trunk prefix 0 + area code 405 + subscriber number).

Geographic Coverage and Administrative Jurisdiction

The 405 area code serves the administrative region of Kolaka Regency, which includes the capital town of Kolaka and surrounding districts such as Pomalaa, Wundulako, and Baula. This area is part of the broader Southeast Sulawesi province, located on the southeastern peninsula of Sulawesi Island. The code is also used for fixed-line services in nearby towns that fall under the same local calling area, including Lasusua and Rante Angin in North Kolaka Regency (Kolaka Utara), which historically share the same numbering area.

Dialing Formats and Caller Instructions

For local callers within the Kolaka area, the subscriber number can often be dialed directly without the area code, depending on the local network configuration. However, for calls from outside the 405 area but still within Indonesia, the format is 0405 followed by the subscriber number. International callers must replace the trunk prefix '0' with the country code +62, resulting in +62 405 followed by the subscriber number. For example, a fixed-line number in Kolaka might be dialed as +62 405 123 4567 from abroad, or 0405 123 4567 from other Indonesian regions.

Numbering and Overlay Considerations

Subscriber numbers in the 405 area typically consist of 5 to 7 digits, making the total national significant number (NSN) length 9 to 11 digits including the leading '0'. Currently, there is no overlay code for this region; 405 remains the sole area code for fixed-line services. As Indonesia continues to expand its PSTN and VoIP infrastructure, the numbering plan may evolve, but as of now, 405 is exclusively assigned to geographic fixed-line services. Mobile numbers in Indonesia use separate prefixes (e.g., 0811, 0821) and are not affected by this area code.

Practical Information for Callers

• Local calls: Within Kolaka, you may dial only the subscriber number (if supported by your operator).
• National long-distance: Dial 0405 + subscriber number.
• International calls: Dial your country's exit code (e.g., 00 or 011) followed by 62 and then 405 + subscriber number.
• Emergency and special services: Always use national emergency numbers (e.g., 112) rather than area-code-based numbers.

When contacting businesses or residents in Kolaka, always confirm the complete number, as subscriber number lengths may vary. For the most accurate and up-to-date dialing instructions, consult your telecom provider or the official Indonesian numbering plan published by the Ministry of Communication and Informatics.