Every Cloyster card we price, most valuable first. Prices are what copies actually sold for, updated daily.
What a Cloyster card is worth
The most valuable Cloyster on this list is Cloyster (8) from Expedition at $91.71£69.03€80.77, and the 13 priced copies across 12 sets are worth $220£165€194 together. Most of that sits in a handful of printings: the older the set and the scarcer the print run, the wider the gap to the rest.
Cloyster is printed in Japanese as well: 15 cards across 12 sets, the most valuable of them Cloyster from Base Expansion Pack at $35.74£26.90€31.48. Switch the list above to Japanese to read those, or to Both to rank the two catalogues against each other.
The highest PSA 10 on record for Cloyster sold for $1,975£1,486€1,739. 1st Edition and reverse holo printings are priced separately from the standard card, because they do not trade at the same money.
If you are trying to identify which Cloyster you have, the set name is printed on the card and the collector number sits in the bottom corner. Open the card here and the page carries every printing of it, the graded prices, and whether grading the copy is worth the fee. Sets to start with: Expedition, EX FireRed & LeafGreen, EX Dragon Frontiers.