Every Rotom Dex card we price, most valuable first. Prices are what copies actually sold for, updated daily.
What a Rotom Dex card is worth
The most valuable Rotom Dex on this list is Rotom Dex (Secret) from SM Base Set at $6.23£4.69€5.49, and the 2 priced copies across 1 sets are worth $7£5€6 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.
Rotom Dex is printed in Japanese as well: 3 cards across 3 sets, the most valuable of them Rotom Dex from GX Battle Boost at $6.58£4.95€5.79. 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 Rotom Dex sold for $40£30.11€35.23. reverse holo printings are priced separately from the standard card, because they do not trade at the same money. Rarities here include Secret Rare.
If you are trying to identify which Rotom Dex 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: SM Base Set.