Will you get blisters walking the Camino - probably. Do you have to get blisters - not necessarily. Nobody wants or plans to get blisters - sometimes it just happens - no matter what you have done to prevent them. While preparing for our Camino - we walked over 125 miles (201 kilometers) - no blisters - until we did one final 26K training walk! We could not figure out what changed. The blister healed before we left but after a few days on the Camino - came back even worse. So we had to take some downtime to rest the foot and let it heal before we resumed walking. We know some people just keep walking - but we do not believe that is the smartest way to cope - no sense causing serious damage or risk getting a foot infection - downtime is good when needed - physically and mentally. It is not a failure - we had to learn that - it is an inconvenience.
To prevent blisters one needs to consider three factors - shoes/boots - socks - wetness. On our recent Camino we saw heavy leather hiking boots - lighter weight hiking boots - lower cut hiking shoes - cross trainers - trail runners - canvas shoes - sandals - all personal preference. Sandals might possibly be a great choice to prevent blisters - they are airy - do not keep the heat in - allow your feet to stay reasonably dry - are lighter weight than other options - however - they allow stones, pebbles and dirt to get under your feet and socks - therefore not our number one choice for footwear. We wore lower cut hiking shoes with a good Vibram sole - never felt any rocks or pebbles that we stepped on. Foot gear must be properly fit - we observed one lady in sandals with the rear strap sliding over her heels like crazy - she was destined for a blister on her heels. Proper fitting footwear (for most) - in general one-half size larger than normal - to allow for thicker wool socks and the swelling that will happen to your feet over the course of the day - the extra length also will help to prevent toe blisters and "black toe" which happens frequently on the rough downhill treks - there are a lot of downhills - to match the uphills - downhills are worse on the feet than uphills. Your foot should fit snug - not tight - the heel should stay in place. Shoes come in wide as well as normal sizes - take that into consideration. There are also different ways to lace shoes and boots - this helps avoid pressure over sensitive parts of the foot - also helps "lock" the heel into place so it fits snug and avoids heel blisters. For a perfect fit - or close to perfect - visit a store - like REI - where the salespeople know how to fit feet properly - they even have a "rock" that you can walk up and down on to help you get the correct footwear. Try on your shoes and boots with the wool socks you will be wearing.
Merino wool appears to be the best for trekking and thru-hiking (the Camino is also thru-hiking) - select the proper sock - you have choices in thickness and length. We started with knee high socks and switched to ankle length during our training period - hot summer walking ankle length is best - early spring, late fall standard better - winter - knee length will work better. Spend the money and buy a good brand of sock - you will be happy you did. We tested Smartwool and Darn Tough socks and settled on Darn Tough - mostly for the length. Some people like to double sock - others wear a synthetic liner that helps wick the moisture away from the foot as a first layer in a two sock system - others prefer socks that are two socks in one - the inner part is the synthetic material bonded to a wool outer layer. New on the foot wear scene is "finger" socks - there are various brands - many swear that these completely helped prevent the sheer action on their feet which is what causes blisters. No one system is best for everyone - so you have to test and try.
So you got a blister - now you have to take care of it. Rule #1 - do not remove the dead tissue on top - it will protect the skin underneath. Although many might recommend not opening up the blister - the fluid inside is what causes the pain - walking on an untreated blister will only irritate it more to the point that the blister will rupture on its own and open up. Better to open it yourself - to avoid the pain factor - avoids a tear in the skin - creates a smaller clean opening - and treat it properly. One system used in European countries quite often is referred to as "needle and thread". Basically the blister is wiped with a disinfectant wipe - the needle and short section of thread is also wiped with the disinfectant - the needle is then carefully inserted into the white dead skin on top of the blister all the way through - carefully pulling the thread through so that you have thread hanging out both puncture points - the thread is then cut - leaving you with a surgical drain - the thread acts as a wick to drain the fluid out of the blister - the dead skin on top is a barrier to protect the nude skin underneath. You may gently apply pressure to the blister to help the fluid drain.
The next day when you want to walk the blister should be flat - leave the thread in until completely healed - use moleskin or molefoam to "picture frame" around the blister - do not put on the blister - just around it - donut fashion - with the blister in the center - this takes pressure off that part of the foot. To go one step further wrap some gauze around the foot - over the moleskin to keep in place - then - going for the gold here - take a strip of duct tape the length of the bottom of your foot and place on top of the gauze. The duct tape holds all this in place - on top of the duct tape apply your Body Glide or Vaseline - then put on your sock. You now have treated and are preventing further damage to the foot and you have created a slippery surface on the bottom of your foot to almost completely avoid the sheer forces mentioned above. Once the blister is completely healed you may go back to normal - or if you think it may happen again - just wrap that part of the foot with gauze and continue using the duct tape to create a nice preventative barrier for the remainder of your Camino. No - duct tape is NOT easy to find on the Camino so bring some from home in your first aid kit. Carrying a small first aid kit - one for each couple - walking team - should be enough - band-aids - gauze - scissors - are the most common items used - you can also add antibiotic ointment - but these are readily available at the Farmacia. Current treatment for minor cuts and scratches is not to use antibiotic ointments - rather clean and cover with Vaseline and an appropriate bandage.
Remember these are only hints - you should only use those you are comfortable with - check with your doctor or medical practitioner if unsure - also make sure none of this conflicts with any medical condition you might have or medication you are taking. Common sense goes a long way on the Camino.
Dale and Arlene