I used to buy mostly Rip Curl wetsuit, and when they decided to reverse the chest zips, I was puzzled, but after the first session, I was convinced:

Chest zippers must open towards the inside

Why?

• Reduced stress: The natural tension on the wetsuit doesn't pull the zipper open. This eliminates the need for a cumbersome stopper or a snap button, as it cannot come undone on its own in the water.
• Greater range of motion: The "inside" end of the zip is free from the bulk of the starting mechanism, allowing for a wider opening. This makes getting in and out of the suit noticeably easier.
• Durability: The stress of entry and exit is concentrated at the "open" end of the zipper, where it is less likely to cause damage.

The picture on the right is of my Feral wetsuit. It’s an excellent Yamamoto neoprene suit, but it is cut a bit smaller in the chest than other brands. Because of this, I actually blew out the zipper during only my second session—something that has never happened to me before.

I had it reversed by a local repair shop (the excellent All-In repairs), and the difference is staggering. The wetsuit feels noticeably looser and more comfortable in the chest!

My advice:

• Prioritize wetsuits with reverse zippers.
• Standard zippers can be reversed by your local wetsuit repair specialist.