One key issue for models of bilingual memory is to what degree the semantic representation from one of the languages is shared with the other language. In the present paper, we examine whether there is an early, automatic semantic priming effect across languages for noncognates with highly proficient (Basque/Spanish) bilinguals. Experiment 1 was a "between-language" masked semantic priming lexical decision experiment. Results showed a significant between-language semantic priming effect for both Basque-Spanish and Spanish-Basque pairs. Experiment 2 showed that the magnitude of the "between-language" and "within-language" masked semantic priming effects was quite similar. Experiment 3 replicated the findings of Experiment 2 with highly proficient bilinguals whose mother tongue was Spanish. Thus, highly fluent bilinguals develop early and automatic between-language links with noncognates at the semantic level, as predicted by the hierarchical revised model and the BIA+ model. We examine the implications of these results for models of bilingual memory.