eBay might be your best bet. 

You could always ask your local PGA Professional to order them for you.

Hey, you're lucky you can even find a hat.  There are several golf shops listed on the Titleist web site that don't carry Titleist head wear at all.  I'm trying to find a Bucket and Aussie hat.  

I would love to know the answer too! I have a small head and the S/M are just too big. I am considering taking a hat I got to a tailor to see if he can alter it, but I'm afraid that would mess it up...

I'm pretty sure that the fitted hats made by New Era only come in three sizes:  S/M, M/L, and L/XL.

Their fitted hats are all made in s/m, m/l, l/xl. They come from New Era. Keep trying them on. Many of their hats vary in size and you will probably find one that fits.

Team Titleist  PLEASE bring back the fitted hats from 4-5 years ago!!  I still have an old one Sku:  RN 70547

These were the best hats you have ever produced b/c as you worn them, the fabrick molded to your head shape and size without any winkle issues....also, the depth of the hat was perfect which has been an issue for you in many newer models....the stretch fitted ones of today do not do model appropriately as they age.  The adjustable ones end up with wrinkle issues at the top as they age....the hats from the SKU above have a huge following....Red, Blue, Grey, Orange...all Great!!  I have discussed this with many friends and everyone always agrees....please bring them back!!