Cardiff Half Marathon

Why this race belongs on a competitive runner's shortlist

Cardiff gives PB chasers a fast half marathon with the scale and landmarks of a larger event. The route links Cardiff Castle, Principality Stadium, Cardiff Bay, and Roath Park, and every finish counts toward the six-race SuperHalfs passport. Its World Athletics Elite Label and large field add competitive depth. The Penarth rise and possible wind across Cardiff Bay are the two places where the flat-course reputation needs some context.

Course overview

Cardiff starts on Castle Street outside Cardiff Castle and heads past Principality Stadium and Cardiff City Stadium before climbing toward Penarth. The route drops to Penarth Marina, crosses Cardiff Bay Barrage, passes the Senedd and Wales Millennium Centre, then turns north for Roath Park and the Civic Centre finish. The model totals 65 m of ascent, with the main climb before Penarth and a smaller late rise toward Roath Park.

Kilometers 0 to 5

The start outside Cardiff Castle passes the Principality Stadium and Cardiff City Stadium while trending down from the center. Water is available at mile 3, about 4.8 km. Use it only if planned, keep the crowded opening controlled, and prepare for the first meaningful rise toward Penarth just after this section ends.

Kilometers 5 to 10

The main early climb comes on the road toward Penarth, followed by a drop to Penarth Marina and the Cardiff Bay Barrage. Water and HIGH5 gel are offered at mile 6, about 9.7 km. Hold effort on the rise, take the gel with water if it matches training, and regain pace only after the descent.

Kilometers 10 to 16

The route crosses Cardiff Bay past the Norwegian Church, Senedd, and Wales Millennium Centre on low, mostly flat roads. The waterfront can be exposed even without much climbing. Water and sports drink are at mile 9, about 14.5 km; take the practiced drink there and judge pace by effort if the wind is coming across the bay.

Kilometers 16 to 21.1

The late course rises gradually toward Roath Park, loops the lake, and then heads back to the Civic Centre. The final on-course water station is at mile 11, about 17.7 km. Take a small drink if needed before the loop, keep effort steady on the rise, and wait for the return toward the center before increasing pace.

Elevation checkpoints and how to read them

The route model totals 65 m of ascent, with a high point around 27 m. The main early rise comes after 5 km on the road toward Penarth; the barrage and Cardiff Bay sit lower and flatter, while the northbound approach to Roath Park adds a gradual late rise before the course drops back toward the Civic Centre finish.

Aid stations and race-day logistics

Water is on Penarth Road at mile 3, water and HIGH5 gel are at Roald Dahl Plass at mile 6, water plus sports drink follow mile 9 on Ninian Road, and the final water point follows mile 11 on Lake Road West. The start is on Castle Street, with bag drop from 08:30 on Museum Avenue. Use city-centre public transport and walk to the pens. The organizer has not yet published a more specific 2026 station-to-start or park-and-walk plan.

Practical pacing plan

Hold back from Cardiff Castle through the stadium section before the main rise toward Penarth. Control that climb, then return to goal effort across the lower Cardiff Bay Barrage and bay roads. Wind across Cardiff Bay, or rain on the barrage turns, should change the split. Cap effort on the gradual rise toward Roath Park. Push after the lake, when the course turns back toward the Civic Centre.

Historical weather pattern

Historically, race-month temperatures in Cardiff have ranged from about 39°F to 64.9°F, with winds around 6.4 to 14.4 mph and measurable precipitation on 76.6% of sampled days. Conditions can change, so check the race-week forecast before you travel and again before race morning.

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