which is easier to do?

it is easier to go from infield to outfield IMO,
fly balls are easier than grounders and you don't need to be that accurate or fast.

And in the outfield you get very few "smashes" where you literally have no time to react. Not saying that outfielders do not need good reaction time, just not the same as a shot at the third baseman.

OPP

Speedy,

I think the footwork required by good infielders is more challenging to learn than the footwork that outfielders must learn.

JMHO

No question. Infielder to outfielder. An outfielder with good baseball sense, however, can make the transition to infield reasonably quick with some good coaching. It depends on how much time you have for the transition.

Infielder to outfield is a much easier transition, you can read a flyball at any position but you need a different read for groundballs at each position.

I know of some colleges that pretty much try to recruit shortstops--and turn them into outfielders--as the thought is the SS is the best athlete on a team.

IMO
Infielder to Outfielder

Infielder to outfielder, but not any infielder. Your best athletes can play any position, that's why shortstops can make the move to the outfield. Older outfielders move to first base quite often. Many times you can get away with poor outfield play but it always seems to bite you at the wrong time. Try moving a slow first or third baseman to the outfield or a weak armed second baseman out there. The results will be disasturas over a season. In fact any position change at the higher level is difficult. Just look at all the opposition players give to changing positions in the majors.

Infielder to Outfielder....assuming foot speed is a given....

Have to go with the general consensus - inf to of is the easier transition.