We see many people mentioning that they get iodine from Celtic Sea Salt.
I don't dispute that it does contain some iodine. But the amount might be rather less than we tend to imagine.
I went to one company's web site (Selina) and checked on their plain Celtic Sea Salt.
Q. Does Celtic Sea Salt® contain Iodine?
A. Celtic Sea Salt® has a naturally occurring, trace amount of iodine. It’s approximately 0.68 parts per million. Though iodine an important mineral component, sea salt is not considered a significant source of it. Yet sea salt is an all-natural, pure source of iodine that is quickly absorbed and stored by your body!
A salt labeled as “iodized” typically means that iodine was chemically added to the salt, possibly using an artificial additive to bind the iodine to the salt. We do offer a natural answer. Our Celtic Sea Salt® Gourmet Seaweed Seasoning contains 350 mcg of iodine per ¼ tsp. It’s a truly natural, iodine-rich sea salt.
0.68 parts per million is the same as 0.68 milligrams per kilogram. Or 680 micrograms per kilogram.
The standard iodine requirement is usually set at around 150 micrograms a day.
If you relied on Celtic Sea Salt alone for that, you would need to consume around 220 grams of salt a day.
You might also notice that they produce another product which, because they add seaweed, contains much more iodine. But that has another name and is not just Celtic Sea Salt.
Note: This is for background information and is not in any way advice to take iodine.