Play around with your hair placement. That matters a lot. Mine will only stay on if I keep it in a low tight bun at the base of my skull.
Someone posted this some time ago, and I’ve reposted it several times. To do this, I ordered all of the things she mentions, including an extra big cap. On me, this cap completely covers my ears, but I don’t have long hair.
For long hair, I find latex works best. They just don’t slip like the silicone ones and they cost pennies comparatively. I like to put my hair in a pony and not a bun and then tuck the ends into the back of the cap. This way, you don’t have a big hump on your head that the cap has to go around. If your cap is pulled down over your ears, then they should help keep the earplugs in place. I find the standard silicone putty ones work fine for that.
Any of that helpful?
I bought some Speedo ear plugs these ones and recently a new silicone swim cap this one and they’re both really working pretty great for me. I have long hair too, the swim cap fits right over my big head, hair (tied back in a bun), and my ears which keeps the earplugs in nice and snug.
Can’t help you with the cap, but I’m a huge fan of these TYR silicone earplugs. They do a moderate job of staying in, so I just either cover them with my cap or with my goggle strap, but they do a decent job keeping water out. I’ve never been able to get wax earplugs to work, but these have worked well for me.
Swim caps slip off mostly because of conditioner in your hair. I grew up in the 60’s and 70’s and swam in college in the mid-70’s. Back then, we NEVER wore swim caps — as amazing as that seems today.
I do a braided bun; I feel like the extra compression and texture help keep the cap from slipping.
I wear two latex caps. Snug and stays.
Try a different brand of swim cap. I had that problem with name brand caps (Speedo, Tyr etc.). An inexpensive house brand cap from Tri Boutique.ca stays put. Go figure. The only difference that I can see is that the house brand cap is softer and stretchier.
Tear the wax earplugs in half. It’s too much wax. I do this for the kids I teach, and they work so much better. Give it a try.
Rinse hair before swimming. Pull ear up and out then mold the silicone plug inside your ear. Make sure the swim cap covers your ears.
I use witch hazel on my face to get off any oils, rinse my hair and face before putting on the cap; works great!
Speedo does a long hair swim cap; have you tried that one? I have even found wearing the cheap rubber ones on first (super stretch and sticky) then silicone over the top. How are you putting your hair in? I’ll have to do a tight scrape back into a bun or pony with a plait and make sure a single cap is on SKIN.
@Oaklan
The long hair Speedo is the one that didn’t even last me a lap today. I normally just put my hair in a high bun.
Sparrow said:
@Oaklan
The long hair Speedo is the one that didn’t even last me a lap today. I normally just put my hair in a high bun.
Really? I just got one, and it was okay. I went with a back bun. Like, it did come off my ears a bit, but that was it. My hair is thick and mid-back.
I don’t use a cap. I jump in and get my hair fully wet first, then make a super tight low bun with a thick rubber band that has little rubber lines on it for extra grip. My hair never comes loose, all strokes / all speeds. Caps drive me nuts.
I have a massive lion’s mane of hair. Curly and unpredictable. My cap always slipped off with each push-off, but once I started REALLY drenching my hair pre-swim, the cap seemed much more secure. I then bend over, flip my wet hair over, and put the cap on that way. Then just tuck everything in around your face. You want the weight evenly distributed! Not all gathered in one big bowling ball at the back of your head 
Try the Mack’s AquaBlock ear plugs if you haven’t yet—I have them and love them, they’re comfortable and easy to use as long as you follow the directions that come with them.
Blu tack. Best ear plugs ever.