For a true test of endurance and fitness, many athletes like to challenge themselves with a swim-bike-run triathlon, or even a run-bike-run duathlon. Long Island has some competive races to choose from.

And for those who want to help a good cause and stay fit, too, a number of charity walks are coming up this summer as well.

TRIATHLONS, MULTISPORT EVENTS

SMITH POINT SPRINT TRIATHLON, Smith Point County Park, County Road 46, Shirley, eventpowerli.com 500-meter swim, 16k bike, 5k run. Fee See website. Date 6:50 a.m. Aug. 13.

RUNNER’S EDGE TOWN OF OYSTER BAY TRIATHLON, Theodore Roosevelt Park, West End Avenue, Oyster Bay, 516-349-7646, glirc.org Half-mile swim, 15k bike, 5k run. (Event for ages 8-13 9:15 a.m. Aug. 26.) Fee See website. Date 7 a.m., Aug. 27.

MIGHTY HAMPTONS TRIATHLON, Sag Harbor, eventpowerli.com 1.5k swim, 40k bike, 10k run. Fee See website. Date 6:40 a.m. Sept. 10.

advertisement | advertise on newsday

UJA-FEDERATION AQUA RUN RACE AGAINST POVERTY, Tobay Beach, Ocean Parkway, Massapequa, 516-762-5857, my.ujafedny.org/aquarun 800-meter swim, 3-mile run. Also, 3-mile walk/run. Benefits UJA-Federation. Fee See website. Date 8:30 a.m. Sept. 17

MIGHTYMAN HALF IRON AND OLYMPIC DISTANCE TRIATHLON, Fort Pond, Montauk, eventpowerli.com Half iron: 1.2-mile swim, 56-mile bike, 13.1-mile run. Olympic: 1.5k swim, 40k bike, 10k run. Fee See website. Date 6:50 a.m. Oct. 1.

MIGHTYMAN MONTAUK SPRINT TRIATHLON, Fort Pond, Montauk, 631-259-4516, eventpowerli.com 750-meter swim, 17k bike, 5k run. Fee See website. Date 6:30 a.m. Oct. 1.

BRANDS CYCLE AND FITNESS FALL DUATHLON, Cedar Creek Park, 3340 Merrick Rd., Seaford, 516-442-0117, raceawesome.com 1.1-mile run, 11-mile bike, 1.1-mile run. Fee See website. Date 8:30 a.m. Oct. 7.

 

CHARITY WALKS

BLADDER CANCER AWARENESS WALK, Center for Science Teaching and Learning, 1450 Tanglewood Rd., Rockville Centre, 516-369-2376, ampupbcan.org Walk on trails; games, face-painting, animals, snacks. Fee $25, $10 children. Date 12:30 p.m. May 21.

CONGENITAL HEART WALK, east pavilion, Sunken Meadow State Park, Kings Park, 516-355-8475, congenitalheartwalk.org Benefits congenital heart causes. Just under 3 miles. Register 9 a.m. Fee Donations accepted; $8 parking. Date 10 a.m. May 21.

GREAT STRIDES FOR CYSTIC FIBROSIS 5K WALK, Indian Island Park, Riverhead, 516-827-1290, greatstrides.cff.org (This walk, normally held in Westhampton Beach, is in Riverhead in 2017.) Register 9 a.m. Kids activities, food. Fee Donations accepted. Date 10 a.m. June 4.

GREAT STRIDES FOR CYSTIC FIBROSIS 3K WALK, wildlife center, 249 Buckley Rd., Holtsville, 516-827-1290, greatstrides.cff.org Register 9 a.m. Fee Donations accepted, $5 parking. Date 10 a.m. June 11.

advertisement | advertise on newsday

TAKE STEPS LONG ISLAND FOR CROHN’S AND COLITIS, Belmont Lake State Park, North Babylon, 516-222-5530, cctakesteps.org/longisland2017 Fundraiser; music, food, kids activities, educational materials; 11:30 a.m. registration. Fee See website. Date 1 p.m. June 11.

WEST END 5K WALK FOR ALZHEIMER’S AND FALL FESTIVAL, Marjorie R. Post Community Park, Merrick Road, Massapequa, 631-820-8068, adrcinc.org Benefits Alzheimer’s disease center; register 8:30 a.m., noon festival, lunch. Fee Donations accepted. Date 11 a.m. Sept. 9.

WALK NOW FOR AUTISM SPEAKS, Field 5, Jones Beach State Park, Wantagh, 631-521-7853, autismspeakswalk.org/longisland; 3 miles. Fee Donations accepted. Date 8:30 a.m.-1 p.m. Oct. 1.