How far is the Hubble Bubble?

The Hubble Bubble offers 6 distances: 10K (6.2 miles), 10 Mile (16.1 km), Half Marathon (21.1 km / 13.1 miles), 20 Mile (32.2 km), Marathon (42.2 km / 26.2 miles), Ultra Marathon (52.2 km / 32.4 miles).

Is the Hubble Bubble course marked?

Yes, the course is marked. Navigation skills are not required.

When is the next Hubble Bubble?

Sat, 31 Oct 2026, 08:30. Entries open.

It's Grim Up North Running Hubble Bubble

Leeds & Liverpool Canal, Wyther Lane, Kirkstall, LeedsSat, 31 Oct 2026

The Halloween one at Kirkstall: 10k to ultra along the flat Leeds & Liverpool towpath, fancy dress encouraged, spot prizes for the best of it.

Distance	Ascent	Per km
52.2 km Ultra Marathon	—	—
42.2 km Marathon	—	—
20 Mile	—	—
21.1 km Half Marathon	—	—
10 Mile	—	—
10K	—	—

canalflatMarked course

Nobody has reviewed this one yet

No reviews of the Hubble Bubble, and nothing on what people wore. Both are things no organiser publishes and every runner wants before they enter — how it actually went, and what was on your feet.

Ran it? Write the first review

Running it soon? Connect Strava and we will ask you about it the day you finish, so you do not have to remember to come back.

Pick your distance

starts 10:00

What you’re in for

The Halloween one. Fancy dress is encouraged and there are spot prizes for the best of it, with distances from 10k to the 52.2km ultra on the last day of October. The course is the Leeds & Liverpool Canal towpath from Wyther Lane in Kirkstall, an out-and-back that turns at a marshal and comes back the way it went. Kirkstall Abbey is a few minutes along the bank, Headingley is the nearest station, and there is no parking at the start — it is street parking and a walk. The longer distances repeat the out-and-back: the marathon is the half twice, and the ultra is two half laps and a 10k on top.

Terrain and trail

Surfaced towpath the whole way, flat apart from the ramps at bridges and locks, and wide enough to pass on. It is the fastest ground Grim run on: a PB course if you want one, and a kind one if you are stepping up a distance. Puddles and a bit of mud where the surface gives out near the bridges, and it can be icy in the winter events. Feed stations roughly every three miles with drinks, sweets and cake, and the events are cup-less, so bring your own cup or bottle. A GPX is supplied and not every junction has a marshal, so know where the turn is. Over-ear headphones are not allowed, and some road crossings are unmarshalled.

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Train for it: routes near the start

Routes starting within 20 km of Leeds & Liverpool Canal, Wyther Lane, Kirkstall, Leeds, nearest first. Each one has a free GPX file and a TRP grade, so you can rehearse the ground before race day.

MODERATE

Washburn Valley from Leathley

10.2km · 167m climb · Loop · 12km away

You get a quiet string of reservoirs and river woodland a stone's throw from Otley, with none of the crowds of the honeypot dales. It is the sort of route locals keep to themselves.

MODERATE

Shipley Glen and Baildon Moor

12.7km · 215m climb · Loop · 12km away

You start at the World Heritage village of Saltaire, run the canal and the wooded ravine of Shipley Glen, then climb to the trig on Baildon Moor for a proper moor-top view over Airedale.

VERY HARD

The Ilkley Skyline

35.1km · 808m climb · Loop · 14km away

Eleven kilometres of unbroken moor crest, then you cross the valley and run the skyline back the other way with your entire morning laid out in front of you. It is the biggest day available from an Ilkley train station.

HARD

Burley Moor Stone Circles from the Cow and Calf

11.6km · 320m climb · Loop · 17km away

Four thousand years of prehistory in one loop. Rombalds Moor carries over 400 cup-and-ring marked stones, and this route strings the best of them together before dropping you onto two kilometres of Burley Moor that almost nobody runs.

MODERATE

The Twelve Apostles and Rombalds Moor Trig from the Cow and Calf

7.7km · 248m climb · Loop · 17km away

You touch the highest point of the moor and a Bronze Age stone circle inside eight kilometres, on paths good enough to run nearly all of. It is the best hour available on Ilkley Moor.

MODERATE

Ilkley Moor from the Cow and Calf

9.5km · 287m climb · Loop · 19km away

You run straight up onto the moor of the famous song, past the Cow and Calf crags and out to the Twelve Apostles stone circle, with cup-and-ring carvings scattered underfoot.

Checked Jul 2026

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How to enter

Sat, 31 Oct 2026 · Entries open · £5–£56

Enter on their website ↗

Entries are handled by It's Grim Up North Running, not by us. We take nothing for sending you there.

Add to your calendar · with the start time

Common questions

: The Hubble Bubble offers 6 distances: 10K (6.2 miles), 10 Mile (16.1 km), Half Marathon (21.1 km / 13.1 miles), 20 Mile (32.2 km), Marathon (42.2 km / 26.2 miles), Ultra Marathon (52.2 km / 32.4 miles).
: No course file for the Hubble Bubble yet, so there's no measured climb here. When It's Grim Up North Running publish one, this fills in.
: Not graded yet. A TRP grade is worked out from distance and climb measured off the course file, and there isn't one for the Hubble Bubble yet.
: Yes, the course is marked. Navigation skills are not required.
: We don't hold a compulsory kit list for the Hubble Bubble. It's Grim Up North Running confirm mandatory kit in their race information, usually in the final instructions.
: We don't hold published time limits for the Hubble Bubble. If It's Grim Up North Running set cut-offs, they'll be in the race information.
: We don't hold a checkpoint list for the Hubble Bubble. What's on the table varies a lot between races, so check the It's Grim Up North Running race information rather than turning up expecting food.
: Not yet — we don't hold a course file for the Hubble Bubble. Some organisers only send the GPX to entrants. If we get one, it goes up free, with no sign-up.
: Sat, 31 Oct 2026, 08:30. Entries open.