We conducted a reciprocal transplant experiment to test the effect of tidal exposure on the microbial symbiont community of the intertidal sponge H. heliophila. In a North Carolina tidal creek, we transplanted sponges from the subtidal to the intertidal and vice versa. We characterized the microbial symbiont community of H. heliophila before and after experimental transplantation using next-generation Illumina sequencing of 16S rRNA gene sequences.