The U.S. Postal Service will be holding extended holiday hours at the Honolulu main post office near the airport, but is reminding customers of convenient, self-service options, along with a list of holiday mailing tips.

For Hawaii residents, the Postal Service provided the following suggested mailing dates for letters, cards and packages to reach their destinations by Christmas:

>> Dec. 6 for first-class and priority mail headed to international and overseas military destinations.

>> Dec. 19 for first-class and priority mail headed to the U.S. mainland.

>> Dec. 21 for expedited priority express shipping service mail headed to the U.S. mainland.

The dates apply to mail received by each Post Office’s cutoff time.

The USPS expects to process and deliver more than 13 billion pieces of mail and 800 million packages between Thanksgiving and New Year’s Day this year. The week of Dec. 16 to 22 is predicted to be the busiest mailing, shipping and delivery week.

Letters and packages sent shortly after the suggested dates may still make it to their destinations before Christmas, according to the USPS, but ultimately, unpredictable factors such as mailing volumes and weather determine whether deliveries can be made early or on time.

The Honolulu main post office near the airport will stay open two hours later than usual on Dec. 7, 14 and 21. Its operating hours on those days will be 9 a.m. to 6 p.m.

Customers can purchase stamps, print and pay for postage for packages and conduct other common transactions at convenient postal kiosks, without waiting in line or seeing a mail clerk.

These Self Service Ship & Mail Centers are available 24/7 at 16 locations in Hawaii including the post offices at Aina Haina, downtown Honolulu, Hawaii Kai, Hilo main, Honolulu main/airport, Kailua, Kailua-Kona, Kaneohe, Kapahulu Safeway supermarket, Kihei, Lahaina, Makiki Post Office, Mililani, Waialae-Kahala, Waikiki and Wailuku.

The USPS offers the following mailing tips for the holidays:

>> Save money with flat-rate boxes: Customers can send up to 70 pounds in medium flat-rate boxes to domestic locations for only $14.35. The large flat-rate box, which holds 50% more (with the same 70-pound limit) is available for only $19.95, and features the tagline “Seasons Greetings from Hawaii” printed on its side.

>> To support military troops overseas, up to 70 pounds can be shipped in the military large flat-rate box to most APO and FPO locations for only $18.45.

>> Save time. Pay for your postage and print out your mailing label at USPS.com, then notify the Postal Service at usps.com/pickup that they’re ready to be picked up. Your carrier will pick up your packages from your home or office, usually the next business day. There is no extra charge for this service. Prepaid packages can also be dropped off at a post office without waiting in line.

>> All Priority Mail and Priority Express envelopes and boxes now include day-specific delivery, improved tracking and free insurance. Priority Mail and Priority Express envelopes and boxes, including a limited supply of special “Seasons Greetings From Hawaii” large flat-rate boxes, are available for free at your local post office.

>> The USPS delivers Express Mail on Christmas Day in major U.S. metropolitan areas. Ask your local postal clerk to determine whether this option is available for your holiday packages.

The USPS receives no tax dollars for operating expenses, and relies on the sale of postage, products and services to fund its operations.