This paper reports on an experimental study of the use of two Spanish markers of epistemic modality and evidentiality, creo que 'I believe that' and pienso que 'I think that', by native speakers, and by Dutch and German learners of Spanish. We found a clear preference for creo que among the native speakers of Spanish, but with differences between the main varieties of the language. For Dutch and German learners the preference for creo que was significantly weaker, and for beginning learners of Spanish it was significantly weaker than for advanced learners. While for the Dutch learners of Spanish this pattern reflects the preference for I think over I believe in their L1, the preference that the German-speaking learners have for creo que can be seen as evidence for a general tendency noticed in the literature, namely the interference of an L2 (in this case English) instead of the L1 (in this case German) in L3 performance (in this case Spanish).