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Costa Slack Tide

rated 4.5 of 5 stars
photo: Costa Slack Tide sport sunglass

A little bit of fashion meets a little bit of adventure. The Slack Tides have some limited flexibility but they make up for it in generous padding and lightweight design. The Green Mirror lens offers unprecedented contrast.


  • Polarized lens
  • Generous Hydrolight padding at points of contact
  • Outstanding clarity and pop with Green Mirror lens
  • Lightweight


  • Limited temple arm flexibility


During the spring, summer and early autumn, I tested three different styles of Costa sunglasses (Rincondo, Slack Tide, and Rincon). Each featured a different lens and frame, allowing me to test multiple variables when considering Costa sunglasses. This test is for the Costa Slack Tide with Green Mirror polycarbonate lenses. You’ll see a comparison to the other two at the end of the review.



For three warm-weather seasons, I wore the Costa Slack Tide sunglasses while fly fishing, hiking, and scouting for whitetail deer and elk, as well as everyday uses like casual bike rides. 



Construction and Features:

The Costa Slack Tides are a little more casual looking than most adventure sunglasses, but don’t let that fool you, they are fully capable shades for many outdoor pursuits. The construction of the Slack Tides includes a generous amount of Hydrolite rubber which acts as a non-slip contact point on the nose and behind the ears (a positive) but also a one-way temple hinge that limits the overall flexibility of the frames (a negative). The bioresin frames are lightweight, weighing in (with polycarbonate lens) at 1.02 oz (29 grams). The Slack Tides also feature an open attachment point for certain types of retainers/straps, although the only ones I’ve used with these frames are over-the-top style retainers. 

A little hard to see in this photo, but the rubber grip at the nose and end of the arms is liberally applied. 


Fit and Comfort:

It can be tricky to find the right size of shades without trying them on first. Costa’s website has a size and fit guide for each pair of sunglasses, with the frame sizings running narrow, regular or wide (they mention that most folks go with regular) and the frame size can vary from small to extra large, which is the overall size of the lens (i.e. how much face does the lens cover). 

Prior to trying the Slack Tides, I had previously experienced some sizing issues with the Rincondos, which share a similar frame fit (regular) but was one size larger in overall frame size (large). With this in mind, the Slack Tides fit well and are comfortable over long periods of continuous use.  




While I try not to be particularly hard on sunglasses my 1-year daughter doesn’t exactly share my thinking. She grabs, pulls, smudges her slobbery little fingers all over my sunglasses. In addition to my daughter’s fingers, the Slack Tides have also been with me on numerous hikes, getting dropped at least once that I recall while climbing over a downfall tree that was blocking the trail. No immediate signs of wear or loose components at this time. I do get a little nervous taking them on and off, as the hinge doesn’t flex as much as the other models I tested, but no signs of wear or loose components at this time. 


A view through the 580P (polycarbonate) green mirror lens on the Costa Slack Tides.


The Slack Tides come with a zippered hard case and a lens cleaning cloth. I’ve used these both extensively, and the case is my go-to spot for storing the shades. It’s easy to stash into a pocket in my hiking pack or into a car’s cupholder and go, without needing to worry about damaging the shades. Together, the case and cloth weigh 2.47 oz (70 grams).  

Grasshopper not included. Carrying case and cleaning cloth are included.


Comparison to other Costa models:

As previously stated, I tested three models of Costa sunglasses (Rincondo, Slack Tide, and Rincon). Each have a slightly different frame and each with a different lens. When comparing these three pairs, I’m taking into account primarily the frame shape, size, and fit, and secondarily the lens type and color. I’ve listed the details below, along with a distinct advantage and disadvantage for each. Depending on the criteria you use to determine a good pair of sunglasses, I hope the below comparison helps highlight how these three models of Costas, along with their respective lenses, stack up against one another. 

Rincondo (full review here):

  • Size: M
  • Frame Fit: Regular
  • Frame Color: Matte Smoke Crystal
  • Frame Advantage: Do-it-all frame that can easily make the jump from backcountry needs to lifestyle needs.
  • Frame Disadvantage: Only two frame colors to choose from.
  • Lens Type: Polarized Polycarbonate - 580P
  • Lens Color: Gray Silver
  • Thoughts on Lens: Solid everyday option of lens color. 
  • Weight: 1.02 oz (29 grams)


Slack Tide:

  • Size: L
  • Frame Fit: Regular
  • Frame Color: Black/Shiny Tort
  • Frame Advantage: Most padding and grip (Hydrolite) allows for a very secure feeling without weighing them down.
  • Frame Disadvantage: No internal hinge at temple, limiting flexibility.
  • Lens Type: Polarized Polycarbonate - 580P
  • Lens Color: Green Mirror
  • Thoughts on Lens: Everything pops with incredible contrast with the green mirror lens. Great for fishing freshwater, bird watching, hiking with uneven footing, and mid-summer deer scouting. Easily my favorite lens of the three I tested. 
  • Weight: 1.02 oz (29 grams)


Rincon (full review here): 

  • Size: XL
  • Frame Fit: Wide
  • Frame Color: Shiny Black
  • Frame Advantage: Full coverage for big heads without looking bulky or chunky.
  • Frame Disadvantage: Even though they aren't ginormous, they will still look excessively large on a small-to-average headsize. 
  • Lens Type: Polarized Glass - 580G
  • Lens Color: Blue Mirror
  • Thoughts on Lens: Glass lens tends to show more smudges than polycarbonate lens, not to mention glass costs more. Blue mirror is best for really sunny days and lots of reflection. 
  • Weight: 1.41 oz. (40 grams) 



Conclusion and Recommendation:

The Costa Slack Tides are dubbed an “athleisure” frame, meaning they are more for looks, but able to go on an adventure if necessary. I’d say this is a pretty fair categorization of the frames, thanks to their great grip and lightweight design. The Green Mirror lens are where this pair really shines the brightest (no pun intended). This lens provides the absolute best contrast I’ve ever experienced in a pair of sunglasses. 

I’d recommend the Slack Tides for those with an average to slightly above average head size, and needing a good amount of lens coverage and for those who want a pair of shades with a sense of fashion. I’d also highly recommend the Green Mirror lens for those wanting a high contrast (e.g. sight fishing, deer scouting, bird watching, etc.) pair of sunglasses. 


I’ve had a love/hate relationship with sunglasses for a long time. I used to never wear them because I couldn’t find a pair that fit properly or they’d just break or become lost. I typically rotate between three types of sunglasses at all times—one pair of high performance sunglasses from a reputable brand like Costa, Oakley or Smith that are usually expensive but offer the best performance, weight, polarization, etc. (used most often on hikes, low-impact fishing trips, and for style), one pair of semi-cheap polarized lens that can get beat up or lost and I’m not too upset about it (used for fishing trips where there is a higher chance of me taking a spill), and one pair of crappy convenience store frames that cost less than $10 that probably won’t last more than a year or two and easily scratch (typically used when mowing the yard).

Source: received for testing via the Trailspace Review Corps (Sample for testing and review provided by Costa)

About the Author

Tyler (KiwiKlimber) is a hiker, hunter, and mountain biker who roams the ridges and valleys of Central Pennsylvania (USA). Occasionally, he helps facilitate team-building initiatives and high ropes challenge courses. His hiking and hunting friends know him as the guy who always packs extra food, no matter what.

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Price Current Retail: $172.00-$292.00
Historic Range: $99.99-$292.00
Frame Fit Regular
Size L
Product Details from Costa »

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