I can bi-lateral breathe when I swim but it hasnt been pretty. I pretty much felt like my stroke fell apart if I breathed to my left. I read a couple of posts on here about it and one piece of advice stuck out.....make sure you exhale completely before breathing in. I noticed I did it no problem to my right but was holding my breath to the left. Concentrated on exhaling and boom....no problem....ok, still not as comfortable as my right side but definitely better.