The Honolulu Marathon starts Sunday at 5 a.m. at Ala Moana Park and finishes at Kapiolani Park.

Around 27,000 people are expected to register for the 26.2-mile footrace, plus another 5,000 for the Start To Park 10K; also about 2,000 are expected for the Kalakaua Merrie Mile on Saturday, according to numbers provided by marathon president Jim Barahal.

Around 10,000 volunteers and paid workers will be on duty Sunday morning. Also, many of the expected 35,000 off-island visitors who will either participate or are with participants have already arrived on Oahu.

Lawrence Cherono (2 hours, 8 minutes, 27 seconds) and Brigid Kosgei (2:22:15), both of Kenya, won the men’s and women’s races in course-record times last year.

A week before race day, the forecast for Sunday in Honolulu from The Weather Channel’s website was a high of 78 degrees, a low of 71, partly cloudy with a 10 percent chance of rain, winds at 21 mph and 63 percent humidity.

Race pack pick-up is at the Marathon Expo at the Hawaii Convention Center on 1801 Kalakaua Ave., from Thursday through Saturday, starting at 9 a.m., closing at 6 p.m. on Thursday, 7 p.m. on Friday and 5 p.m. on Saturday. Also, late entries are accepted during those hours (online registration is closed).

All registered runners must pick up their own packs and have valid identification. A help desk at the registration area of the Expo can assist with issues such as change of address.

The Expo is free and open to the public. Massages, sports gels and sunglasses are among the many marathon-related services and products for sale there. A free shuttle runs from stops in Waikiki to the Expo and back. See honolulumarathon.org for times, stops and other information.

Traffic detours along the marathon route will start Sunday at 12:30 a.m. Areas of downtown, Kakaako, Ala Moana, Waikiki, Diamond Head, Kahala and East Honolulu will be affected. There will be lane closings, tow-away zones and rerouting of TheBus.

The route runs to Kakaako, downtown and continues through Ala Moana, Waikiki, Diamond Head, Kahala and into East Honolulu. Runners turn around in Hawaii Kai and head back to the finish line at Kapiolani Park.

Traffic questions can be directed to info@honolulumarathon.org or 808ne.ws/2B111Tu.