2026 Portsmouth Coastal Marathon - Dec 20 Countdown

Q: What is the Portsmouth Coastal Marathon route?

The Portsmouth Coastal Waterside Marathon is a flat out-and-back that starts and finishes on the Southsea seafront by the Pyramid Centre / South Parade Pier. Runners head along the promenade, cross over to Hayling Island and run down the Hayling Billy Trail beside Langstone Harbour to a turnaround, then retrace the same line back. It is a multi-terrain coastal course rather than a closed-road city race.

Q: Is the Portsmouth Coastal Marathon flat? How hard is it?

The course is genuinely flat - only around 108m of total ascent with no real climbs. The challenge is not the gradient but the mixed surface and the winter wind: the first miles are paved promenade, then the Hayling Billy section turns to shingle and soft mud that can sap your legs, and an exposed seafront headwind on the return can be brutal. On a calm, firm day it is a fast, friendly marathon; in wind and mud it runs much tougher than the profile suggests.

Q: What surface is the course and what shoes should I wear?

It is a multi-terrain course: the opening three miles are paved Southsea promenade, then sections of shingle beach, muddy path, a couple of bridges and hard-pack towpath along the Hayling Billy Trail. Many runners choose trail shoes or grippy off-road trainers for the muddy, shingly middle, while road shoes are fine on the promenade. After wet December weather the Hayling section can be properly muddy, so prioritise grip over cushioning.

Q: How do I enter the Portsmouth Coastal Marathon 2026?

Entry is open to the public online through organiser Believe and Achieve Events (fitprorob.biz), with no ballot. The marathon fee is around 37.99 GBP, and the same weekend also offers a half marathon and a 12K. There is no lottery - entries simply close when the race sells out, so this cult winter event is worth booking ahead.

Q: What time does the Portsmouth Coastal Marathon start and what is the cut-off?

The marathon starts at 08:30 from the Southsea seafront on Sunday 20 December 2026, with the event running to mid-afternoon for a generous time limit of around 7 hours. The early start makes the most of the short December daylight, so plan to finish well before dusk. Pace your effort with our pace calculator and sanity-check a flat finish time with our finish time calculator.

Q: Is the Portsmouth Coastal Marathon a Boston Qualifier?

No. Because the route includes off-road shingle, mud and trail sections rather than a fully UK Athletics road-certified, accurately measured road course, a Portsmouth Coastal finish is not valid for Boston qualifying (BQ) or a London Good For Age (GFA) entry. Come for the flat profile, the sea air and the low-key winter atmosphere, not an official qualifying time. If a qualifying mark is your goal, check the standards with our Good For Age tool and pick a certified road race.

Q: How do I get to the Portsmouth Coastal Marathon, and where do I stay?

The start is on the Southsea seafront in Portsmouth, on England's south coast and well connected by train - Portsmouth & Southsea and Portsmouth Harbour stations are a short ride or walk away, with regular direct services from London Waterloo in around 90 minutes. Plenty of seafront hotels and guesthouses sit within walking distance of the start, making this an easy car-free winter race; book early, as it falls right before Christmas.

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Race Information

Race	2026 Portsmouth Coastal Marathon - Dec 20
City	Portsmouth
Date	2026-12-20 at 08:30
Time Limit	7 hours
Cutoff pace	9:57/km
Timezone	Europe/London
Official Site	Believe and Achieve Events
Registration	Register · 37.99 GBP

Race Day Weather

Average Temperature	6.1°C / 43°F
Humidity	95%
Wind	27.6 km/h
Rain Chance	46%
Typical Conditions	A raw, breezy mid-winter morning on the exposed Solent coast. Expect around 7-8C (46F) at the 08:30 start, climbing little through the short December day, with high humidity, a real chance of rain and a stiff wind funnelling across the open seafront and Langstone Harbour. Mild by UK-winter standards but the wind chill on the promenade bites.

What to Prepare: Dress for single-digit Celsius plus wind chill - a windproof layer, gloves and a hat make the exposed seafront sections far more comfortable. The first miles are paved promenade, but the Hayling Billy Trail turns to shingle and mud, so trail shoes or grippy trainers help. With the year's shortest days, expect flat grey light; run by effort and keep moving to stay warm.

Based on historical averages for race week. Use our Weather Score Calculator and What to Wear Guide for personalized advice.

Wind Impact on Race Day

Wind at 27.6 km/h can affect your marathon pace by 5-15 seconds per kilometer. Headwinds slow you down exponentially — a 20 km/h wind costs more than twice a 10 km/h wind.

Calculate your wind-adjusted pace →

Race-Week Climate

Based on 20 years of race-week weather (2005-2024), MERRA-2 reanalysis

	Cooler	Typical	Warmer
Temperature	0.9°C	6.6°C	10.2°C
Dew point	0.1°C	5.9°C	9.4°C

Wet-day chance: 46% Runnability: 58/100

Data: NASA POWER (MERRA-2 reanalysis), NASA Langley Research Center

Course Profile

Course Type	Flat out-and-back along Southsea seafront to Hayling Island and back
Elevation Gain	108m
Terrain	Mixed
Profile	Genuinely flat at roughly 108m of total ascent - there are no real hills, so the difficulty is the surface and the wind, not the gradient. The first three miles run along the paved Southsea promenade before the route crosses to Hayling Island and heads down the Hayling Billy Trail to the turnaround, then retraces the same line back.

Prepare for 2026 Portsmouth Coastal Marathon - Dec 20

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What to Wear Running by Temperature — Clothing Guide

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Dew Point Running Calculator — Pace Adjustment Chart

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Wind Effect on Running — How Much Does Wind Slow You?

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Frequently Asked Questions

What is the Portsmouth Coastal Marathon route?

The Portsmouth Coastal Waterside Marathon is a flat out-and-back that starts and finishes on the Southsea seafront by the Pyramid Centre / South Parade Pier. Runners head along the promenade, cross over to Hayling Island and run down the Hayling Billy Trail beside Langstone Harbour to a turnaround, then retrace the same line back. It is a multi-terrain coastal course rather than a closed-road city race.

Is the Portsmouth Coastal Marathon flat? How hard is it?

The course is genuinely flat - only around 108m of total ascent with no real climbs. The challenge is not the gradient but the mixed surface and the winter wind: the first miles are paved promenade, then the Hayling Billy section turns to shingle and soft mud that can sap your legs, and an exposed seafront headwind on the return can be brutal. On a calm, firm day it is a fast, friendly marathon; in wind and mud it runs much tougher than the profile suggests.

What surface is the course and what shoes should I wear?

It is a multi-terrain course: the opening three miles are paved Southsea promenade, then sections of shingle beach, muddy path, a couple of bridges and hard-pack towpath along the Hayling Billy Trail. Many runners choose trail shoes or grippy off-road trainers for the muddy, shingly middle, while road shoes are fine on the promenade. After wet December weather the Hayling section can be properly muddy, so prioritise grip over cushioning.

How do I enter the Portsmouth Coastal Marathon 2026?

Entry is open to the public online through organiser Believe and Achieve Events (fitprorob.biz), with no ballot. The marathon fee is around 37.99 GBP, and the same weekend also offers a half marathon and a 12K. There is no lottery - entries simply close when the race sells out, so this cult winter event is worth booking ahead.

What time does the Portsmouth Coastal Marathon start and what is the cut-off?

The marathon starts at 08:30 from the Southsea seafront on Sunday 20 December 2026, with the event running to mid-afternoon for a generous time limit of around 7 hours. The early start makes the most of the short December daylight, so plan to finish well before dusk. Pace your effort with our pace calculator and sanity-check a flat finish time with our finish time calculator.

Is the Portsmouth Coastal Marathon a Boston Qualifier?

No. Because the route includes off-road shingle, mud and trail sections rather than a fully UK Athletics road-certified, accurately measured road course, a Portsmouth Coastal finish is not valid for Boston qualifying (BQ) or a London Good For Age (GFA) entry. Come for the flat profile, the sea air and the low-key winter atmosphere, not an official qualifying time. If a qualifying mark is your goal, check the standards with our Good For Age tool and pick a certified road race.

How do I get to the Portsmouth Coastal Marathon, and where do I stay?

The start is on the Southsea seafront in Portsmouth, on England's south coast and well connected by train - Portsmouth & Southsea and Portsmouth Harbour stations are a short ride or walk away, with regular direct services from London Waterloo in around 90 minutes. Plenty of seafront hotels and guesthouses sit within walking distance of the start, making this an easy car-free winter race; book early, as it falls right before Christmas.