The present invention relates to carrier-linked prostanoid prodrugs of formula (I) Z1—(X0-L0-PG0)y (I), wherein Z1, X0, L0, PG0 and y have the meaning as indicated in the description and claims; pharmaceutically acceptable salts thereof and pharmaceutical compositions comprising the same. It further relates to their use as medicaments, especially for treating, controlling, delaying or preventing pulmonary arterial hypertension.