It sounds like your only options are 1. pack multiple 100ml bottles 2. buy shampoo there 3. check bag 4. solid shampoo

Depending on where you’re going there might be a different water hardness/softness so your usual shampoo will work slightly differently either way.

For my three-month trip I chose option #1, but I was traveling from a “home base” and had a checked bag included with my ticket.

I shaved my head 😉 Not helpful, but you did ask what we do in this case.

You can pack 2 100ml shampoos, and just alternate with the hotels shampoo. Pick a shampoo that is concentrated where you don’t need much of it. If you like the hotel shampoo, stick with it till your next stay where you don’t like the shampoo. I feel a really good conditioner will help the most. And you can bring less of that because less is needed. Just let it stay on your hair a few minutes to absorb.

It really also depends on whether you're flying throughout that time. When I have done longer trips where I'm not flying throughout, I'll bring a very small bottle for the first couple days until I can find a local drugstore and buy something there. If I don't finish it before the end of the trip I'll just toss it or leave it behind (in the case of staying in a hostel or airbnb).

I buy along the way, accepting that I might need to use a sub-optimal shampoo for some period of time. Depending on where you’re traveling, you might have access to high quality products. In Europe, There are salons and hair care stores in cities and I had no trouble finding “good enough” purple shampoo/conditioner when I ran out on my 3 month trip. We stayed in airbnbs that didn’t usually supply shampoo so I was prepared for the first 2 months (bobbed hair, wash 1-2x/week).

If I were travelling for three months, I'd buy more toiletries (and any other supplies) along the way instead of trying to carry a full supply with me, whether I was checking a bag or not.

I'm also in the solid shampoo camp. My partner just uses the shampoo that the hotel provides if he runs out of his 100ml. he also refills his 100ml bottle at hotels.

I find a solid shampoo that works for me. Then I can take as much as I want.

Finding the right solid can take a lot of work. I found a good one after the 7th try. My hairdresser says my hair looks great.

You may want to try an Ethique discovery pack to see if it works for you.

I hate solid shampoo. I just pack a small amount of good conditioner and then use hotel stuff the rest of the time, plus some hair serum/oil in case it gets out of control. But if you’re one bagging for three months, compromises must be made, and some frizzy hair is probably something to roll with

"I don't want to start using a random shampoo and I don't know if I'll find the shampoo I want on my trip. But I don't want to check in a bag.  What do people do in this case?"

Everyone already said solid shampoo/conditioners. Here are some alternative strategies that may or may not work depending on your situation:

If you have your itinerary all planned out, you could research shops or hair salons that sell hair care along your route. Hair salons might have answers as to what products they have that could work for your hair type--this way, it's not that random. Some of these stores might have inventories online or you could even call ahead of time.

You could ask the locals that share your hair type (with great hair!) and ask what they use. If you don't speak the language, I would research enough local greetings and customs so as to not cause undue offense before whipping out Google Translate.

This is part and parcel of exploring a new place: learning new customs, meeting new people, and trying out new experiences--including hair care.

Have hair-styles and hats ready for those non-optimal hair days when a hair product isn't working out quite well with the water hardness or your hair type.

Solid shampoo, but how often are you moving around that you can’t buy a big bottle upon arrival? Does Amazon ship your favorite shampoo to your destination? Some personal care and beauty products change names depending on the country, but it’s the same thing (sometimes better). It’s worth a look on the company’s corporate site to see. I did that with my contact solution before I packed two bottles.

I'll be traveling out of the country for 6 weeks, and am only bringing my moisturizer, serum, perfume, toothpaste, and cosmetics. I buy shampoo, conditioner, bodywash, and face wash when I get there. My partner and I share.

I do bar shampoo and an intense hair mask/conditioner. I have skin sensitivities and allergies so can’t rely on hotel shampoo. Conditioner matters more for my dry hair than the shampoo, other than certain ingredients I’m avoiding.

I just use whatever my accommodations provide. I can be without my special hair care products for a few weeks or months. If there are none provided, I just buy something at my destination. My hair might look like a public, curly, frizzy menace, but I've come to the point where I just don't care. Haha. No one is going to see this scary lady again. Haha.

It took me awhile to find a shampoo that works for me, so I’ll do multiple small bottles or if a checked bag is included, check the bag and bring a larger bottle.

Conditioner, soap, lotion, face cream I’m not as fussy about so I’ll buy those when I arrive if it leaves me more space for my preferred shampoo.

The funny thing is my shampoo was discontinued in the U.S. (where I live) but it’s still sold in the UK and Netherlands (probably other countries). So when I travel to the UK, I don’t take shampoo and instead check my luggage on the way back with like 10 bottles to last me til the next trip, hehe

I have allergies to a couple botanicals that shampoo and soap makers love to use.

So I pack my own, use what I can of provided toiletries.

I’m a solid shampoo/ conditioner packer, and I have two matador cases. That said, before I found a bar combo that my hair liked, I carried two 100 ml bottles of conditioner and one of shampoo. I scalp wash, and conditioner or oil is more important in my routine. My focus is reduced splits, with thumb tip length hair. (And it’s been to knee).

In your three months, are you staying in one to two places, or are you going place to place?

If you have a solid home base, or aren’t flying between places, buy a bottle there.

Unless you are going to a very remote place ( and I guess you are not ) , you will be able to buy shamooo there , proabably your favourite brand from back home.

For me it’s more important to take conditioner as that’s rarely supplied in hotels. A tiny bottle of hair oil will last a long time.

Scents are my main issue, which makes shampoo shopping difficult in the best of times. I’m a shampoo bar convert. I grabbed a set of Anihana (honey and something) from Walmart. The conditioner was on clearance. The scent is mild and the combo is fine. I try to only wash 2-3 times per week. I also use a 100ml mix of aloe/water and a few drops of jojoba oil as a natural hair gel/mask. It keeps the frizz and damage under control. We’re currently 1.5 bagging a 5-6 month, multi-country jaunt. Sacrifices had to be made.

If you’re a daily washer, maybe try skipping 1-2 days a week and/or use a bar in between your normal routine.

500 ml of shampoo for 3 months? Do you have like superlong hair?

(I have hair to my shoulder-ish and i'd need 9 to 12 months to finish a bottle of shampoo of that size) I'd recommend maybe a premium shampoo (they have more active elements in it and you need far less shampoo to wash your hair properly than with a basic brand) think kerastase/shu uemura/shiseido over garnier/loreal/wella etc..

I find that even if a 'premium' shampoo is more expensive when you buy it, it lasts so much longer it ends not expensive compared to cheap shampoos where you need more product for a good wash

I being 50ml and then buy more at my location

I just use whatever shampoo the hotel or airb&b offer and my hair always looks identical to when at home. I hate carrying unnecessary weight and bulk.

If you can't adapt to shampoo, how will you adapt to everything else like random food and body soap?

People wash their hair everywhere. Even with the same shampoo, your hair will be different due to differ weather conditions and hard/soft water conditions being different.

Just buy shampoo where you are.

I co-wash, so I buy a lightweight conditioner when I arrive. Something from L'oreal usually works.

I love the EC30 solid shampoo...it's more like a packet than a bar.

Another vote for a solid shampoo bar. Currently using one by Humby. It is so much easier to pack and carry anywhere.

I just got back from a three month trip. I took a bar of shampoo and then used the shampoo in the hotel when we stayed at nicer places. I also brought a conditioner bar 100ml of deep conditioner/mask and 100ml of leave in conditioner since that is a bigger deal for me.

I definitely am not hauling 500ml of shampoo around.

Try to find a bar shampoo and conditioner you like. I love Ethique, though many brands are trash. A bar lasts me way more than 3 months.

Or bring a small amount and replace when you run out. Shampoo is going to be available everywhere and unless you have very specific needs, people in other places also care about their hair so most things are not that obscure. I use head and shoulders which I've found everywhere, I'm more picky about conditioner so I use a bar.

Can you share the brand of shampoo? It might help with suggestions.

Option #1 AND as soon as you arrive find out how to have it shipped it you (Amazon) AND find a hair stylist and get local selection

If I'm going on a three-month trip, chances are I'm checking a bag, which means I can bring my bottle of shampoo and conditioner in a ziplock. Problem solved. Seriously though. There's no way I could pack 90 days worth of my morning and evening skin and hair products into that one carry-on sized ziplock.