These reusable ear plugs with a cord or leash keep the water out. Unlike the foam ones, they are easy to insert, more durable and dependable. These are the ear plugs I use and I can tell you I've tried everything on the market before landing on these. So many of them slide out of the ear or were tough to insert and get them so they blocked the water.
I don't find any other type that seals the water out better. Besides doing a stellar job keeping water out of your ears during water sports and the shower, Ear Seals are great for ear/hearing protection when shooting, or attending loud events like racing.
Mack's Ear Seals with removable cords.
These ear plugs can stay on the cord or you can pull them off. They come with a nice carrying case, too.
You do not have to fit or size them. They are pre-molded flanged ear plugs. Mack's ear plugs feature a dual durometer design where two plastics are used in the molding process.
What does this mean? The outside is tapered, soft and flexible to mold to your ear and seal water and noise out effectively. The stiffness of the stem helps with the insertion. And they are tough enough to protect you from swimmer's ear and surfer's ear.
Carrying case is nice for transporting.
Let's face it, ear plugs are not large items and they can get gross hanging randomly about a gym bag. So the little plastic case is a nice feature.
Reusable makes them very cost effective.
Buy Mack's Ear Plugs
They run about $3 for four ear plugs. I don't have to buy them often either. Usually, these four will last months. But I would recommend replacing them in 6 weeks to 2 months if you are an avid swimmer or surfer and want the tightest fit for an athletic event.
They are also comfortable enough. I'm not going to love any of them in my ear but these feel the best.
I will warn you, though. You don't need to push them too far down the ear canal because if you do, you will become dizzy and off balance. All you do in that case, is pull them out a bit. So insert them slowly and you'll quickly get the hang of how far you can push them in. This is because if you push them in too far, they upset your vestibular nerve, referred to as your balance nerve.
Also recommended Mack's AquaBlock Ear Plugs at Amazon. These are not corded.