While it may not be the traditional set up for a scuba regulator, I find it just makes more sense to have the alternate air source on the left and not the right. The alternate air source, safe second or octopus whatever you prefer to call it is typically set up on the right side of the first stage and I think that it is something that most divers just accept. But if we really look at the design of regulators and alternate air sources I think it is more functional to be on the left.
Before we get into why I think it should be on the left let me put a couple things out there that not all divers will agree with largely because of their training. And if you disagree with me that is fine I think all divers should dive with the set up they are most comfortable with.
- There is nothing that says the alternate air source has to be on the right side. No training agency specifically states which side the alternate has to be on for recreational diving. Yes it is most commonly on the right but I think that is just because thats now it has always been.
- The alternate being on the left does not change the process of sharing air. You still pull the alternate from the keeper, clip or pocket, clear it from under your arm, give it to your buddy and make contact with your buddy.
- The alternate air source is for my buddy. I do not believe in donating my primary to a panicked diver or a diver that is out of air. The hose for the alternate is designed to be longer so a buddy can use it, and I shouldn’t have to breath off a less tuned regulator because my buddy was not paying attention to their air.
- Overhead environment, A majority of my diving occurs in California with the kelp forest and there are times where going straight up while sharing air can cause more problems so an ability to swim comfortably with a buddy who is using an alternate air source is very handy.

My first reason for diving with my Alternate air source on the left is no kink in the hose when sharing air. Because of the orientation of the regulator in order to share air with a buddy (if oriented on the right) the hose has to kink, or bend back on itself reducing the length of the hose, this also makes it pull out of the divers mouth and honestly a little awkward. It is also common to avoid this kink for divers to present the alternate upside down to their buddy which for some alternates can cause them to leak water, or not work at all, often making the situation worse. By placing the alternate on the left these problems are all resolved, the hose does not kink, it does not have to be given upside down, and the divers are allotted appropriate space.
My second reason for placing my alternate on the left is body positioning for sharing air. The traditional position (for PADI at least) is to make contact with your buddy once air is being shared by linking right arms. This is all well and good if you are going straight up but if you need to swim out from under something like a dock, boat or kelp, it can be a little awkward. Now with the alternate on the left this can still be done, but I prefer to grab onto the bcd with my left hand when I am donating air so i can help control their buoyancy with the right shoulder dump, and give the receiver both hands free to manually inflate at the surface while I am still holding onto them, this avoids any bumbling at the surface and I can use my buoyancy to help them stay afloat until they are inflated without losing contact. I understand that this may impede my ability to deflate as we ascend because my left hand is occupied but I also dive a drysuit so I am raising my left arm anyways to deflate.
My third reason is kinda over arching of all of these, it comes down to training. One of the biggest reasons people stick to the alternate on the right is because of the fear that is instilled upon them that another diver is going to run out of air and pull their primary out of their mouth. While the logic behind this appears to be sound, a panicked diver is looking for a working regulator will go for the one that they see is working, I believe that is a failure on the part of their instructor. I have been diving for almost 20 years with 1000+ dives and never have I once seen a diver grab a regulator out of my or anyone else’s mouth. I know for sure that my students were trained better than that to endanger another diver. The alternate is made a bright color for a reason so it is visible for the other divers to find in an emergency. I have been on dives were divers have run out of air and each time they either signal to me or grab my alternate because thats how they were trained. If you train someone to pull a regulator out of someone else’s mouth then they will and that could cause a whole other mess of problems.
While I personally prefer to have the alternate on the left this is my own opinion, I believe that the benefits of having it on the left are much higher than having it on the right. With that being said I also believe that personal equipment should be set up to each divers personal preferences and if this convinces some divers to try it out on the left great but I understand that those of us that prefer our alternates on the left will remain a minority. I hope that this has been enjoyable and maybe made people question why their regulators are set up the way they are.