Explore 360

Snowdon Sea to Summit

  • Where?


  • Altitude


  • Duration

    1 days

  • Weather

  • Physical


  • Technical


  • P3 - This trip is physically tough. Frequent exercise is necessary to prepare properly for this expedition. Regular walking mixed with training at the gym to build up endurance and cardiovascular fitness is key. Expect to be able to do 8 hour days in hilly and often steep train, carrying a pack of 6-10kg in weight with the occasional extra long day.

    Visit our Grading Information page for a full overview.

  • T2 - Consider this a trek, although there may be occasion to use hands for short sections of easy scrambling. No previous climbing or trekking experience is necessary.

    Visit our Grading Information page for a full overview.

  • Overview

  • Date & Prices

  • Pics & Vids

  • Itinerary

  • Kit List

  • FAQs


From the shores of Caernarfon to the heights of Yr Wyddfa (formally known as Snowdon), this ‘Sea to Summit’ trek sees you ascend to the highest point in Wales.

Yr Wyddfa is the highest peak in Wales and at 1085m/3560ft high, it’s a good stomp to reach the summit. However, you are rewarded with tremendous views over the coast and across northern Snowdonia from its lofty heights. If the cloud obscures these fine views from the summit, as it often can, there is still plenty of exciting mountain terrain to make this an adventurous day out.

Steeped in history, the dramatic rocky outcrops and secret cwms en route add even more charm to this Castle to Castle trail taking in some of the most iconic vistas Wales has to offer.

This is a RAW 360 event – find out more about our UK team here

Find out more
Snowdon Sea to Summit Snowdon Sea to Summit

Date & Prices

For private trips or bespoke itineraries inc. different dates, please contact the 360 office on 0207 1834 360.
A monthly payment plan is possible, please contact the office to chat through the options.

For private trips or bespoke itineraries inc. different dates, please contact the 360 office on 0207 1834 360.
A monthly payment plan is possible, please contact the office to chat through the options.

We currently have no scheduled dates for this expedition, however if you give the office a call on 0207 1834 360 it would be easy for us to get this up and running.


  • Incredibly experienced RAW 360 guide required to safely support and lead the group and give you the best experience possible with a 1:10 ratio radio dedicated coordinator
  • Professional and expert challenge event organisation and management
  • Pre-event support and training advice
  • Group safety equipment
  • Full public liability insurance cover
  • Cotswold Outdoor discount
  • Monthly payment plan, on request

Not Included


  • No meals are provided – please bring your own snacks, packed lunch and water to sufficiently keep you going throughout the day. Make sure you eat breakfast at least 60 minutes before you start walking. You need to carry at least 2 litres of water, plus juice drinks. Please bring your own meals and always pack a variety of foods
  • Travel insurance
  • Personal equipment
  • Personal drinks and extra snacks

Pics & Vids


DAY 1 : Sea to Summit - Snowdon (1,085m)

After meeting your Mountain Leaders in Llanberis at 7am, we’ll transport you by coach to Caernarfon Castle. Standing at the mouth of the Seiont river this 700 year old castle is the official starting point for your Sea to Summit challenge. The first half of your journey will be through the lowlands surrounding Caernarfon taking in the Welsh Highland Railway and the Snowdonia Slate Trail.

Upon reaching the Snowdon massif, you’ll cross over the ridge line into the Llanberis valley before your climb begins in earnest. Heading up to Bwlch Maesgwm, the Ranger path will then lead you all the way to the summit. The last part of your journey, will be down the Llanberis path into the village before a quick detour to 12th century Dolbadarn Castle for a final team photo.

(Estimated walking time: 12 hours)

*There will be a briefing, kit check and a chance to ask any questions the evening before the challenge at 19:00*

These are subject to minor changes depending on departure times, weather conditions, group dynamics and fitness and so on, but the itinerary outlined provides an excellent indication of the challenge and what you will experience.

Kit List

Bags & Packs


Approx. 30L capacity. Your day to day pack that you carry with your daily essentials, fitted with shoulder straps and importantly a waist belt

Dry stuffsacks

Nlon rolltop bags (or even just large plastic bags) that keep fresh clothing and other important items dry

Waterproof rucksack cover

To protect rucksack from rain



Essential for protection from the sun and dust


Worth spending money on good UV filters.  Julbo is our preferred supplier

Wide brimmed hat

Keeps the sun off exposed areas like ears and the nape of the neck

Warm headgear

This can be a warm hat, beanie, balaclava, anything to reduce the heat loss from your head


Lip salve

Upper Body

Base layer

(not cotton)

Mid layer

Fleece jacket or top

Soft Shell (optional)

It is useful to pack a spare warm layer in your rucksack

Hard Shell

These jackets are thin, highly waterproof and windproof and worn over all other items of clothing. You’ll find these made of Gore-Tex or other proprietary waterproof yet breathable technology. Inexpensive hard shells that aren’t breathable will prevent evaporation, making you sweat intensely and are not recommended


A light pair of polartec or thinsulate gloves

Waterproof jacket (Outer layer)

Gore-Tex or event seam sealed are recommended and big enough to fit over a couple of layers. This jacket will also serve as a great windproof too

Lower Body

Trekking trousers

These tend to be polyester so they dry quickly after a shower and weigh little in your pack. Consider perhaps a pair with detachable lower legs as an alternative to shorts

Waterproof overtrousers

Like the jacket, an essential piece of kit to stay dry and should also be Gore-tex or breathable, to fit over your summit trousers if needed

These are separate to your trekking trousers.


3-4 season walking boots

Sturdy, comfy boots with ankle support – of course, tried and tested!

Trekking socks

If your feet get wet on the first peak, you’ll appreciate a dry pair on the next so pack a spare!

Quantity: 3


Water bottles / bladder

Filled with water to start


Alcohol gel

A must have for good camp hygiene


Personal first aid kit

The 360 med kits are designed to be used in emergencies and akin to an A&E rather than a pharmacy on Expeditions so please come prepared with useful meds for yourself such as painkillers (Ibuprofen if you can take it and a Paracetamol) plus blister plasters, plasters, antiseptic, rehydration sachets and any muscle rubs you wish to use.

Personal medication

Keep this in your daysack



Bring plenty of spare batteries and memory cards

Head torch

Bring spare batteries or a spare head torch (not a handheld torch or phone)

Trekking poles

These tend to be a personal preference but help with your stability and can dampen the pressure on the knees coming down hill


Feel free to chat to us around advice on fuelling on adventures & see our FAQs for more advice around this.

Packed lunch & drink

Rubbish bag

Taking your rubbish home to keep those beautiful mountains in pristine condition


Travel insurance

Copy of own travel insurance details.  And relevant contact numbers.

We have a partnership with True Traveller and would recommend that you contact them when looking for travel insurance for your trip with 360. However, it is vital that you ensure that the insurance cover they offer is suitable for you, taking your personal circumstances (items to be insured, cancellation cover, medical history) into account. Many other insurance providers are available and we do recommend that you shop around to get the best cover for you on the expedition you are undertaking.

It is your responsibility to ensure that you have the appropriate insurance for your intended trip.  To include medical evacuation and coverage up to the maximum altitude of this trip.


The Challenge

How fit do I need to be for this challenge?

To enjoy and succeed in this event you need to be in good physical condition and able to withstand sustained activity over several hours, including steep ascents and descents. We recommend you partake in active walking/running/swimming/cycling at least 3 times a week to fully enjoy this mountain walk.

The ideal training for mountain walking is getting out there and actually walking in the hills. However, if you do not have the luxury of living in the hills or time to go out, then the stairs at home (or an office block of flats with lots of stairs) are a great place to start training.

We will cover high-level terrain which is rocky and uneven underfoot and remember to include ‘hills’ in any training you do – Yr Wyddfa is not flat! Your muscles and heart need to be used to getting out of breath and working hard. A sense of humour to cope with any adverse weather conditions is also quite beneficial!

What are the group sizes?

We run this challenge with a minimum of 8 trekkers and there is no maximum number – the more, the merrier!


Is accommodation included?

Accommodation is not provided however we can add this on to the challenge is specifically requested. Otherwise, we can provide recommendations.

Do you recommend staying the night before?

It’s very much a personal choice, and will also of course depend on where you’re travelling from.

That said, we would say it makes for an easier start in the morning if you are already in the location. Especially so that you can have a good nights rest before the beginning of your challenge.

Do note also that, depending on where you are travelling to, you may be limited by the last train times from the nearest stations.

Food and Water

What food and drinks are included?

No meals are provided – please bring your own snacks, packed lunch and water to sufficiently keep you going throughout the day.

Make sure you eat breakfast at least 60 minutes before you start walking. You need to carry at least 2 litres of water, plus juice drinks. Please bring your own meals and always pack a variety of foods – both savoury and sweet – that will sustain you during the day.

What do I need to eat to ensure I have enough energy for the challenge?

The following is a guide of what your leader will be consuming over the course of the day. If you are not, then you are likely to be not taking on enough: food=energy and fluids=hydration. Cramping is a sign of dehydration and lack of salts.

Have a large meal the day before your challenge and ensure you are well hydrated i.e. no real discoloration of urine which is sign of dehydration.

On the morning of the challenge have a huge breakfast! Don’t be shy, get it down you as you’re walking not running!

Roughly every 45-50 minutes have a snack whether it is an energy bar, flapjack, banana or a bag of crisps! If you start to feel dizzy/ weak this is a sign you’re not eating enough. Choose complex carbohydrates and whole foods, rather than overly sweet items. Foods like malt loaf, mixed fruit and nuts, cheese and ham, oat cakes, raw fruit bars, dark chocolate, filled wraps, mini pork pies or sausage rolls will last well on the hill and sustain you over a number of hours.

Make sure you take food you enjoy eating as otherwise you will not eat enough of it. You will be burning a lot of calories and need to consume a lot to keep you fuelled.

Health and Safety

What happens if I fall ill, can’t keep up or there is an emergency?

Our Mountain Leaders are well trained and experienced in managing situations on the hill should they need to get outside assistance for example ‘mountain rescue’ they all carry mobile phones and also radios for communication with the minibus drivers.

The Mountain Leader will always keep the group together for maximum safety on each peak and set a sensible pace for all to achieve this challenge. However, if your struggling you must be honest with yourself and the leader remember the top of the mountain is only halfway!

Who will be leading the group?

We employ experienced and fully qualified Mountain Leaders to accompany and lead you with a 1:10 ratio dedicated coordinator. They are mountain first aid trained and have extensive experience in leading in the mountains, your leader will be ultimately responsible for your safety on the mountain and the rest of the group. They will be carrying full safety equipment and mountain first aid kits with them.

You advocate taking a small first aid kit, what should it contain?

We advocate a little bit of self-help on the trek. If you have a blister developing for instance then please stop, take off your boot and treat it before it becomes a problem. Your own first aid kit should contain: a basic blister kit, rehydration sachets, plasters, high factor sun-protection, your own personal medication, and some basic pain relief (aspirin and Ibuprofen). Generally the best approach to take when packing your first aid kit is to include such basic medications as if you would on a family or personal holiday.


What kit will I need on the mountain?

See the comprehensive kit list provided but remember that our seasons now are only determined by the temperature of the rain! You need clothing and equipment for all weathers.

What type of footwear should I be wearing?

The choice of walking footwear is incredibly important and should not be decided on price alone. The terrain is uneven and can be very rough so it is vital that you use a pair of strong canvas or leather boots with good ankle support, not trekking trainers. Not only the boots but the socks that you wear are also very important and it is worth investing in some good pairs of socks. Avoid cotton, trekking or good quality sports socks are advised as are a thin wicking sock to wear underneath if your prone to blisters, these are designed to draw the moisture away from your feet. Wearing your boots and socks during your training period on and off the hills will inform you of whether they are suitable for the challenge.

What should I carry inside my daysack?

A daysack is worn at all times during the trek. The content of this is mandatory and should include: a fleece, waterproofs, warm hat, gloves, sun hat, sunscreen, sufficient water, snacks, camera equipment, personal medication, a head torch and spare batteries and a whistle.

How much should my daysack weigh? What size does that equate to?

Your daysack should weigh no more then 3 – 4 kg (without water) and a pack of around 30L capacity should more than suffice. This rucksack can be filled to brim with extra stuff and you can leave some of it in the minibus between mountains. It is important that this bag has an adjustable waist belt to transfer the weight of your daily load onto your hips and from here onto your legs so that your strongest muscles do most of the carrying.

The Weather

How hot or cold will it be?

The mountain weather in the UK can be very changeable, it can be glorious sunshine down at the base but be wet and windy on the summit. It is not uncommon for it to change from clear blues skies to rain and fog in moments. It is important to follow the advice we give and carry the correct kit.


How do we get to the start of the challenge?

We will meet you at an agreed location in Llanberis at the start of the event and transport you to the walk start point. Your challenge will finish at this same location.

We recommend either arriving into Llanberis the evening before to give yourself time to properly rest and be less rushed on the morning of your challenge.


Do I need special insurance for this expedition?

You must carry individual travel insurance to take part in the challenge. We cannot take you on the mountain without proof of insurance.

It is your responsibility to ensure that you have the appropriate insurance for your intended trip.  To include medical evacuation and coverage up to the maximum altitude of this trip.

Your insurance details are requested on the booking form, however this can be arranged at a later date. 360 Expeditions will be requesting your insurance details 8 weeks before your departure.


How much spending money should I bring?

Depends how many snacks and drinks you want to buy on the way to the start of your challenge! Your evening meal and accommodation will be organised by yourself so you can budget for this.

What is the best time of year to complete this challenge?

From May to September is most advisable for the best chance of pleasant weather.

We can look at October to April however there are far less daylight hours and a greater chance of worse weather.

The literate given to me was clear and comprehensive and I fully knew what to expect.  All in all the weekend was well organised, a great challenge and fun!

Pauline Jenkins, UK 3 Peaks Challenge
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