Call them what you will: Luna Sandals, Luna running sandals, Luna sport sandals, or Luna barefoot sandals! Whatever you call them, Luna sandals are built for adventure!
In this Luna Sandals review, we’ll dive into everything you need to know about the Luna sandals Retro Oso Flaco model.
I have three pairs of the Luna Retro Oso Flaco sandals in various states of wear and overall I love them for hiking, backpacking, and running!
I am excited to share with you my honest Luna Sandals review (the good and bad) about the Luna Sandals Retro Oso Flaco Model to help you decide if they are right for you, or if another model might be better.
Luna Sandals Overview: Sandals for Adventure
Luna launched in 2010 by the founder Barefoot Ted (author of Born to Run), Luna Sandals has created, tested, improved, and grown into the reputable company it is today.
Luna creates adventure sandals. That is, sandals that let you do outdoor activities like hiking and running without sacrificing foot mobility.
If you’re on-board with the minimalist and barefoot footwear philosophy (like I am), then Luna Sandals are a great opinion.
If you are new to minimal footwear, the main idea is to let your feet do their thing, which offers an array of health benefits, including a stronger and less injury-prone body.
Luna Sandals Retro Oso Flaco Overview
The Luna Retro Oso Flaco is part of their Oso model line and retro lacing style. If that didn’t make any sense, don’t worry! We are here to clear up the confusion.
The “retro” is one of the primary lacing styles Luna creates (“winged”) is the other. More on that later.
The “Oso” (meaning bear in Spanish) refers to the tread or traction type. Luna makes a variety of sole thicknesses with the same tread type.
| Lacing Style | Retro. Performance Laces 2.0 with Tech Straps |
| Sole | Waterproof Non-Marking Vibram® Megagrip Outsole + Vibram® Midsole. |
| Sole thickness | 7MM base + 4.5MM lugs |
| Traction | MGT (Monkey Grip Technology). |
| Weight | 7.2 oz (single sandal, men’s size 9) |
Luna Sandals Retro Oso Flaco: Functionality
Pros
The Luna Retro Oso Flaco is thin enough to be mobile and flexible, yet rugged enough to handle a variety of terrain, including rocky and steep trails.
As a result, I consider the Luna Retro Oso Flaco to be an ideal minimalist adventure sandal that you can use on almost any occasion, including long backpacking, hiking, and running trips.
I wear this sandal year-round for all my outdoor activities. It has held up extremely well and I highly recommend it to others looking for a functional adventure sandal.
Cons:
In my experience, where these sandals lack is:
- Highly technical trails (very steep grade or large boulders)
- Lots of scree on steep slopes (small rocks get under your feet)
- Steep trails and wet footbed (due to rain or sweat, can be quite slippery)
Therefore, it’s better to have a closed toed shoe during highly technical trails or steep areas with lots of loose rock. Also, steep trails on a rainy day or hot temperatures (sweaty feet) can lead to a slippery foot bed, but this can be mitigated by wearing socks.
Acknowledging the drawbacks, the Luna Retro Oso Flaco serves my needs 99% of the time I am adventuring outdoors.
Retro Lacing System
The Luna “retro” lacing system is different from their “winged” system.
The retro lacing system has no plastic piece that connects the laces to the sole on either side of the foot. The retro lacing system also has an additional “tech strap”.
The winged system has a “wing” (plastic piece) that connects the laces to the sole.
I have only ever tried the retro lacing system and I find it to be functional, durable, and comfortable.
Sole Thickness
The sole thickness of the Retro Oso Flaco is a 7MM base + 4.5MM lugs. The Retro Oso Flaco is one of their thinner models and the thinnest of the “Oso” line which has this particular lug/traction setup.
| Luna Model | Sole Thickness |
| Retro Oso Flaco | 7MM base + 4.5MM lugs |
| Retro Middle Bear | 9.4MM base + 4.5MM lugs. |
| Retro Oso | 13MM base + 4.5MM lugs. |
In my opinion, the Retro Oso Flaco has an ideal thickness for all outdoor adventures including hiking, backpacking, and running.
I live in a dry climate with lots of rocky trails, and the sole thickness offers the perfect balance of ground feel, flexibility, and protection.
Footbed Traction
The footbed traction of the Retro Oso Flaco is the most technical of all Luna Sandals.
| Luna Model | Traction Rating |
| Mono | Good for Most |
| Leadville, Origen | More Technical |
| Oso | Most Technical |
I find the traction of the Oso sandals to be perfect for steeper grades, slippery slopes, and rocky trails. I even use them in the snow!
Luna Sandals Retro Oso Flaco: Durability
In my experience, the Retro Oso Flaco sandal is quite durable and has met my expectations of an adventure sandal in this regard.
I believe the laces and sole are very rugged and I am more than satisfied at how my Luna’s have held up over the miles I have put on them. I truly feel like these sandals are a great value.
In fact, I have purchased 3 pairs of the Retro Oso Flaco sandals and they all have varying amounts of wear.
My first pair is quite worn down and has actually broken in one spot (the toe strap has disconnected from the sole). That said, I have put a lot of miles on this pair; I would guess between 500 and 1,000.
Also, I know that I can repair the issue easily (when I get around to it) and expect to get a lot of life out of these yet.
My second pair is my “daily driver” and is going strong after around 500 miles or so. My third pair is yet to be touched! I got it during one of Luna’s sales.
Luna Sandals Retro Oso Flaco: Comfort
I find these sandals to be extremely comfortable. As a sandal you are right to be concerned about comfort, as laces might rub causing blisters.
However, in my experience, once I have the laces adjusted properly, I do not get any blisters because of the laces.
In fact, the only time I ever get blisters is on the sole of my feet during long hikes or runs. This is not the fault of the sandal not fitting well, but rather my own skin not holding up. I can totally mitigate blisters altogether by wearing socks if needed.
Overall, I love wearing these sandals and have no complaints about comfort whatsoever. Just know that you might have to trial and error the lace adjustment a bit before you get that perfect fit. Fortunately, the laces are quite easy to adjust and stay in place after adjustment.
Luna Sandals Review: Conclusion
I hope you found this Luna Sandals review helpful. I highly recommend the Luna Sandals Retro Oso Flaco and other models as well, though I only have experience with the Retro Oso Flaco and the Venado (which is great for roads as it has no tread).
If you want the perfect balance of protection and flexibility/ground-feel in a trail sandal, choose the Retro Oso Flaco. The tread is amazing, the lacing system is ideal. I will continue to buy these sandals as my current ones inevitably wear out.
If you’re uncertain of the thickness, lacing style, or tread type, feel free to give someone at Luna a call and they can talk you through the best option for you.