Each conference has different rules for intra-conference transfers. The ACC for example mandates that a player must sit out a year when transferring to another ACC school and lose said year of eligibility (unless they have a red-shirt year). The caveat to this is grad transfers can transfer within the conference without sitting out unless the school the player is transferring from blocks them.
For transfers in general lacrosse players aren't required to sit out a year, its how Nicky Galasso ended up at Syracuse from North Carolina, Ben Williams from Holy Cross, Nick Mariano from Umass etc. Syracuse, Maryland, and Duke have been fairly active in the transfer market the last 5+ years. It may feel like there are more transfers then before because of social media and the increasing popularity of the sport and the number of teams but transfers have long played a role at the D1 level going back years and years.
