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Undulating Half Marathon
This race has taken place

Challenge 21

Haulbowline Island, Cork

Date14 Jun 2026
Start10am
Entry€50/€21
Ascent↑ 71m
Descent↓ 74m
Start10am
Entry€50/€21
Ascent↑ 71m
Descent↓ 74m

⚠ Start times change frequently. Always check with race organiser or their website for this year's confirmed start time before travelling.

Course map

Map based on 2025 route

⚠ This map is for indicative purposes only — routes can change, or be reversed, year to year. Check with the race organiser for this year's confirmed map.

Elevation profile

About this race

Challenge 21 is an annual 21km fundraising walk, jog and run in aid of the Down Syndrome Centre Cork, with the distance symbolising the extra chromosome associated with Trisomy 21. The course starts at Haulbowline Island and follows the proposed Cork Harbour Greenway route along the southern shore of Cork Harbour through Shanbally, Monkstown, Passage West and Rochestown, finishing at SuperValu Páirc Uí Chaoimh in Blackrock. The route is on public roads and is largely flat to gently undulating as it traces the harbour shoreline. Water stations, snacks, stewards and toilet facilities are provided along the route. The event finishes with an inclusive family-friendly finish line party featuring music, food and activities. Now in its fifth year, Challenge 21 attracts several hundred participants annually.

Course profile & record eligibility

World Athletics record-eligibility rules cap net elevation loss at 1m per km of race distance, and require the start and finish to be no more than 50% of the race distance apart — both meant to stop a course gaining an unfair edge from downhill grade or a point-to-point tailwind. This is based on this course's recorded elevation and GPS data, not an official measurement or certification.

Point-to-point Course type
3m limit 21.1m Start/finish drop
11.63km limit 10.5km Start/finish separation
✗ Doesn't meet the course-profile criteria — start and finish are too far apart relative to race distance.