Diving with pump sites and CGMS

Hey ya’ll!
I’ll be getting dive certified this September and I have some questions about diving with pump sites and CGMS on.
I’ve read all the diving info on diving with diabetes and understand I need to lower my basal before diving and be trending up on my BG/ my BG needs to be 150 or higher. I also understand I need to eat before, not have any IOB and I know that I need to check my BG outside of using my CGM a lot before diving. I’ve had type one for 30 years, so I’m well versed in what to do when playing sports or doing rigorous activity. I understand that diving takes a lot out of you and can lower your sugars tremendously so having glucose, extra food and juice is a must as well as having extra supplies.
My question is this I DO NOT PLAN ON DIVING with my pump on, that’s a no go but can I dive with the pump site still on my body or do I need to remove it before diving. Also how do CGMS work with the pressure of diving. Is it safe to keep them (I Understand they will not read my sugars underwater at great depths but will they hurt me if kept on) on or do you have to remove them as well? Has anyone had any experience with dealing with insurance on any of this?
I use the tandem tslim insulin pump and the dexcom G6.
Also I feel I should state my a1c is 6 and has been for almost 3 years now, I take great care of myself. I’m 5.1 and weigh around 150 (NO I am not obese, just a little chubby lol)


If you search, you will find many.
@Marie20 is active member who has experience.

Here is one.

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Thank you so much, ill messge them in the morning but i was hoping someone could tell me about tslim pump sites and dexcom g6 specifically

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I think she uses dexcom normally, but found libre to be better during dives??

Search diving and you will see many posts.

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I use a G6, an Omnipod and a Libre. The Dexcom will not communicate once it’s in water. I’ve held it next to my arm while swimming and held my arm in the air. Every once in a blue moon I can get it to give me a reading, but I can’t count on it. One of the problems is it takes forever to give you a reading once it even connects. The Libre reader I keep in a Stash waterproof pouch and I can get a reading while still swimming immediately when I scan it. My insurance pays for my Dexcom and I self fund the LIbre’s. They are only $37 each for a 14 day one at Costco. I think all pumps and CGM’s have depth limits though. I just snorkel and some limited free diving to see things closer.

I believe @Eric2 scuba dives and is great with advice, but whether he can help you with your specific pump since he wears an Omnipod too I don’t know.

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@Dezclarke89 GU Gels are slim and can slide into your suit? I keep mine slid into my swimsuit. Easy to carry in case you need it. About one out of every 4 times I use one while swimming. Ocean conditions vary so it’s best to be prepared. But again @Eric2 has actually dived and would give the best advice.

Thank you so much! Im reaally trying to see if i can dive with the dexcom on and just take my meter to read my sugars out there. Libres are thay cheap? Have ppl dived with them before?

Also i was thinking i could keep gels on me for sives but womdered how it would be trying to take one at depths under water lol

You would not necessarily have to remove it. But if your pump is not connected, there is not much of a reason to have the site connected, other than making it easier to reattach when you get back in the boat.

And when you reattach, you might be getting some saltwater infused with your next bolus.

Not necessarily a big deal, but personally I would just take the whole thing off and re-attach when the dive was over. That way you don’t need to worry about any issues with the site or anything like that, such as the wetsuit rubbing it and making it loose or anything.

I would just replace the whole thing when the dive was over.

You don’t need to take it off, it won’t hurt you at all. But just make sure it is in a place where you won’t loose your transmitter if it falls off. If it is under your wetsuit, you are will be fine. That way you won’t lose it.

But it will not hurt you if you keep it in.

And as @Marie20 has pointed out…

Those gels are great! If you practice, you can actually eat some of it while underwater!

No really! I am serious. When you open them, they won’t squirt out everywhere underwater, since they are thick.

So you can take out a gel packet, open it, take a breath and hold it (don’t do this when ascending!!!), remove your regulator, squirt some of the gel in your mouth and swallow it (and you will get a bit of seawater too, but that is no big deal), and then you put your regulator back in your mouth and purge it and keep going.

Just make sure you swallow the gel first, otherwise it gets nasty trying to breath!

You might not be doing this, but just know that you can if you have to. Definitely take gels with you.


Just another couple of notes.

The Dexcom doesn’t read underwater even if it’s 6 inches from the surface as the bluetooth just won’t communicate through water. The 14 day Libre and the Libre 2 do with a reader, but I don’t know at what depth they might stop.

The Reader runs about $80 at Costco and the sensors are $37 each at Costco if you belong to their pharmacy club, free to join but you might have to have a Costco membership. There is the phone ap that’s free for the Libre but I don’t know if that works in the water. I will have to try it someday so I know, it’s just I use my phone for picture taking (in a Stash waterproof pouch) and getting the phone to flip screens in water is a trick. The touchscreen is just hard to use. I use the side buttons for pictures or video. My phone goes off and does it’s own thing some of the time, I end up with a picture or video of my leg while swimming a lot.

And I have not run into this because the water I swim in stays 76-80 F. But I gather the CGM’s don’t like cold water. But someone has said they swim in very cold water and the Dexcom will read low for at least 10 minutes after they get out. The Libre supposedly doesn’t like to read in cold water either. Like I said I don’t know, as I haven’t run into that as the water I swim in is a pretty nice temp and I don’t have a clue how cold is too cold for them to work. You should probably take a standard meter with you anyways as you never know when things fail.

Insurance usually only covers a set amount of supplies per month and if one becomes faulty they will refer you to the manufacturer. While Dexcom and Libre replace faulty sensors, they won’t if they know it’s been exposed to ocean water or if it’s been in water for longer than the allowed time.


I do actually scuba dive and am a type 1. I follow the RSTC/DAN guidelines, which you quote with some curious additions, particularly the comment about “IOB”.

I use an Omnipod, so that isn’t covered in the RSTC guidelines. The recommendation is to disconnect the pump before diving (kind of obvious since pumps don’t survive water) and reconnect afterward. I.e. the catheter remains in during the dive.

This doesn’t work for the Omnipod, where the whole shebang is attached to my body. I have dived with an Ominpod attached and I have spent part of the dive underwater listening to my 'pod giving the “duh-duh duh duh” tune that indicates it was dead.

Given that you are a new diver I’m not going to give advice beyond RSTC. Divers are anal retentive at best, for good reason. You will find out how much of what you said is true if you like it and if you don’t, don’t. It’s not quite as dangerous as logging but it’s close. It’s very well worth it if you like it and can live with the very real fear; I recommend Cozumel. 25ft drift dive sites where you can just enjoy it.

Dexcom G6 works fine before/after (tested to 100ft or more), but so what if it fails? I used the G6 as a convenient pre-dive monitor (I normally fingerstick before a dive but in a boat with lots of water it can be difficult). I used the G6 post dive as an invaluable monitor. The numbers are unreliable, but the rise/fall is great. This is particularly valuable for me in river dives where the walk back up (carrying really heavy cylinders) can be exhausting.

The thing about diving is nothing to do with diabetes. If you feel scared do not do it. I only dive with my wife and she only dives with me. I have dived with other people and it was scary. There’s absolutely no reason to do it unless you are completely happy with it, chill out by the pool. Or, for that matter, try paragliding; that’s really great.

Do you have heavy duty over patches so those sites don’t fall off? I always forget them. Dexcom G6 Adhesive Patches and Stickers - ExpressionMed

Your advice comes off a bit weird. Im studying marine biology so diving is a big part of that field. Also being scared of diving with diabetes doesnt mean you shouldnt do it, it means you research and prepare yourself.
Thanks for the advice on the dexcom but as i stated your advice comes off a little weird about the not doing it if youre scared :confused:

I do actually the ones i have are super strong!

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I live massachusetts but i dont think ill have issues with the cold water bc you’re actually not supposed to dive in cold water as a diabetic. Its exacerbates low bs.
Thats all really helpful info :slightly_smiling_face:

You misunderstand. I’m not talking about being scared of “diving with diabetes”, I’m talking about being scared by diving. Lots of people go on recreational scuba courses, don’t like it but get cajoled into going on with it by friends and family.

You can do this…

Here is a little about me. I have been a T1D for 50 years. I was diagnosed with diabetes when I was 6. I went on my first scuba dive when I was 12 years old. I got certified when I was 20 years old.

Keep in mind, my first open water dives were before CGM. And they were also before any real type of basal insulin. Back then we only had the family of zinc suspension basal insulin’s, like NPH.

There was no rapid insulin either! All the bolus insulin was slow and lasted a very long time.

Essentially no pumps either. All the pumps they had were pretty much unusable and impractical for home use.

They did have BG meters, but they were still a bit sketchy. :grinning:

Depending on how long ago you were diagnosed, you will start to get the diabetes part of it figured out.

First big rule - no IOB!!! In general that means you might need to skip breakfast or lunch so that you don’t have any bolus insulin floating around, you just have your basal.

And then you turn your basal off a certain amount of time before the dive.

Do NOT rely on a pump algorithm to adjust your basal! Turn that stuff off and manually do it. Pump algorithms do a lot of wacky changes to your basal, depending on what the CGM says your BG is. That is not the way to go for a dive. Do manual basal adjustments.

Do a lot of BG tests to know what your BG is and which way it is going.

Which BG meter are you using? Unless you said “Contour Next One”, you need to trash that thing and get one of these as your official diving meter. Trust me on this. This is the best meter on the planet.


Does your BG need to be 150 when you dive? Not necessarily. It depends on how comfortable you are with what your BG is doing.

The important thing is not what your BG is when you drop into the water. The important thing is what is your BG going to be in 15 minutes or so when you are down at 100 feet. How long is your dive, how strong is the current, and all that stuff.

But you will get better at that with experience. So using 150 as a starting point is fine until you get better at it and know how a dive will affect your BG.

Please feel free to ask questions!


While all this info is great i need info on cgms and diving ive been a type one diabetic for 30 years so i dont really need advice on that lol. I remember nph, mixing insulins, the days of no pumps, and I also understand how a pump works. I need advice on diving with a cgm and pump site, not on being a successful diabetic. My a1c is 6 so im good there, but thanks anyways!


I would remove pump to dive. I didn’t know you can wear a Dexcom down to 100 feet. It worried me that there might be sealed parts that would implode with the pressure. Good to know that it holds up.

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I have been T1D for 50+ years and was a scuba diver for most of them … even when they said diabetics shouldn’t dive. I took my last dive about 2 years ago because my eyes have gotten to the point that I’m unwilling to risk pressure change on them.

Like most old timers, most of my experience was pre-pump, pre-CGM, heck, even pre-meter.

Here, however, is what I have done, with more modern tools … and I am a t:slim and G6 user.

First, I do carry a couple of the little “frosting tube” gel packs with a twist-off top either in the wrist of my wetsuit or in a BCD pocket.

Second, if you wear your G6 sensor and transmitter underwater, I suggest you do two things:

  1. Make sure that you have an extra transmitter in case the first one goes wheels up. I’m certain that you realize that the transmitter isn’t actually rated (or probably even tested) to withstand the 2-4 atmospheres of pressure to which it will be subjected when diving.

  2. While pressure is a serious issue, salt water is a huge enemy. I travel with a roll of the 5”wide stretch wrap used for packing and shipping purposes. The blue and orange big box stores carry it with a handle to easily roll around your arm, thigh, abdomen, etc. Keeping salt water away from the sensor and or transmitter is a good thing and that wrap will provide a pretty good water seal without sticking to the sensor and pulling it off.

As far as your infusion site, I use the little protective “cap” that comes with my infusion sets … it is the only time that I ever use them … and then, you guessed it, wrap with stretch wrap to keep saltwater from getting too close. I wear my infusion set on my abdomen. Because I worry about scraping my infusion set off when putting on and taking off wet suit, BCD, weight belt, etc, I have a 6” wide, Velcro-attached neoprene “belt” that I wear over my infusion set and plastic wrap to give me one more layer of “scrape resistance”.

Note: I haven’t mentioned any of the basal, BG, stuff that is critical but been well covered already.

Finally, I listen very carefully during the pre-dive description of what to expect: if significant current is expected that I may have to swim against, I don’t dive.

My dive experience: learned to dive in the cold water kelp forests in Monterey Bay, CA. Later transitioned to liveaboard diving (going to/from the dive sites on a skiff) in Fiji.

Happy diving.