I happen to like merino as underwear for various reasons. And on a hot day I like to wear as little as possible without causing offence. Unfortunately, the single bright button on the fly of my Ibex merino boxers is a clear social signal indicating underwear.
I recently discovered Icebreaker Sonic 5" Running Shorts. If you cut out the liner, then you have a wonderful pair of merino boxer underwear that can be worn alone as shorts. It's not see-through (even with the liner removed) and the decorative orange strips on the side clearly signal running shorts rather than underwear. The length is a perfect compromise between 70s shorty shorts and today's over-the-knee, fat-guy-on-vacation shorts. They protect your modesty unless you are getting very long in the scrotum. Leave the liner in if you don't like to swing free while hiking. They probably aren't the right choice if you prefer having your balls tightly compressed (but in that case why are you reading a thread about boxers?).
Like all merino items these are listed for something like $80 but can be found for $40 if you are odd sized (S or XXL) and/or patient. New XXL are $32 on ebay as of this writing. The waistband is comfy merino against skin and substantial enough that I removed the tie strings (S fits my 31" waist and maybe up to 32").
(Apologies to anyone offended by my use of the words fat, shorty shorts, scrotum or balls.)


