Some types of mandarins do have seeds while other types do not.
It depends on how they are grown and pollinated and the variety of mandarins on whether or not they have seeds.
If you pollinate a Mandarin, like a Satsuma or a Clementine, you end up with seeds in the fruit.
Mandarin growers don't want seeds.
It makes them mad – and makes it more difficult to market their Mandarins as “seedless.”
Phoenix mandarins are seedless with a sweet honey flavor.
Amorette mandarins are truly seedless, easy to peel and have a nice balance of sweetness and tang.
But what all mandarin oranges have in common is their easily peeled skin.
The four main varieties, Herbst writes, are clementine, dancy, satsuma and tangerine.
The clementine has sweet, red-orange flesh, a thin peel and is usually seedless.
Dancy oranges are much like clementines but have lots of seeds.
Tangerines have seeds in them.
However, not all types of tangerines contain seeds.
A variety like a satsuma is seedless.
Eating tangerine seeds is not unhealthy.
What is difference between mandarin and Clementine?
The biggest difference is that clementines are a type of mandarin, a hybrid crossing mandarins with sweet oranges, while mandarins are a group of several different fruits that include not only clementines but satsumas, tangerines, and other varieties as well.