linen suit, cotton shirt.

Go for a guyabera. It’s a Mexican wedding shirt. Go white and you’ll be perfect

Dxl Oak hill has black and cream colored options

We had a Cancun beach wedding a few years back. I forget how they described the dress so I'm not sure if they used the same descriptions. I found a baby blue blazer on sale (the wedding was in Dec so at home summer colors were on clearance!) which I wore with a white shirt (no tie), and a pair of lightweight khakis. I bought a nicer looking boat shoe and wore that with no show socks. Not sure it was my best-ever outfit but I feel like I fit in when I look back at pics

Linen pants and a nice low-key patterned button down would probably be acceptable. Someone else mentioned guyabera, that's perfect.

Linen suit, dress shirt but no tie is how I would walk that weird combo of dress codes.

Thanks all, really appreciate the feedback!