SaskTel is reminding customers they should start thinking about dialing 10 digits for local numbers.

This spring, Saskatchewan, home of the 306 area code, is adopting a second code — 639.  It's necessary because the province is running out of 306 numbers due to the growing population.

As a result, 10-digit dialing will become mandatory starting on May 11. Customers will need to add the area code before dialing in the seven digits.

The new 639 numbers go into effect starting May 25.

Seven-digit dialing still works, but as of Monday, people who do that may get a recorded message from SaskTel, reminding them about the coming changes.

Many people who have speed-dial numbers programmed into their home and mobile phones will have to change them.

Businesses will have to reprogram their fax machines.

Some special three-digit numbers — 911 and 411 — won't change.

Meanwhile, people who want to get an early start on 10-digit local calls can go right ahead — adding the area code to local numbers has worked since last year.