The application process is similar, but getting into a competitive prep school in NYC in 9th grade is a lot harder than getting into a competitive boarding school. Mostly because they are all K-12 schools and the spots available in 9th grade are quite limited, Trinity is the only prep school that significantly expands in HS. The single sex schools in particular barely expand so spots are based largely on attrition. And they really do not care much about sports, with the exception of Poly Prep and maybe the hill schools. There are certainly kids that pursue competitive sports and get recruited (mostly D3 but some D1) but that is due to the club and out of school team participation for most part. The school teams vary greatly, depending mostly on how many kids are on travel teams. Soccer is decent, basketball not so much, and football is not competitive at all if it even exists. Catholic schools care more, recruit and have better teams, but mostly out in the burbs not so much in the city itself. In boarding school world the sports coaches have more say and some schools do recruit, though most of the high impact recruits come later than 9th grade. And since they start in HS, there are way more spots to begin with. I do think the line between prep and boarding schools is becoming more blurry as more boarding schools are becoming more like prep schools - getting rid of Saturday classes, increasing the number of day students, and having more students (both day and boarding) who leave campus on weekends and sometimes also weeknights to pursue their extracurricular activities, so continue to have lives outside of boarding school. This is both good and bad depending on whom you ask. Covid has put a pause to it temporarily at least. But as someone already said, if you want to play in college you have to play outside of the BS team because boarding school season is less than 3 months long and even if the coach puts together off season practices once or twice a week it is not enough.