Upvote:1
The least expensive way is to take the M60 from LGA to the Harlem 125th St. stop of the Metro North RR, and take a subway to Penn Station or take the Metro North train to Grand Central Terminal (southbound from Harlem). If you go to GCT, walk 1 mile or take a subway to Penn Station. (The M60 stops in front of every LGA terminal and comes every 10-15 min.) It will cost $2.75 for the M60 and $2.75 for a subway, or a max of $14 for the Metro North (less if off peak or senior.) The trip likely will take you under an hour, more if you have bad luck catching a bus or train.
Also see the reverse directions on this MTA page:
https://new.mta.info/guides/airports/laguardia
and this LGA page:
https://www.laguardiaairport.com/to-from-airport/public-transportation
Upvote:2
Given LaGuardia's location you will have to use Ground Transportation irrespective of where you're coming from at some point of your journey.
The simplest way to get from LaGuardia to Penn Station would be to use the NYC Airporter or a cab. Price will vary but would be as close to a door-to-door as you can get.
Otherwise if you feel like using public transportation just the review the LaGuardia's page on the subject, which lists M60 (to Broadway & 116th Street), Q70 Limited (to subway), or Q47 bus to a subway station and then take one of the lines to 33/34th street station (vary depending on the line) and then walk. Would probably come out cheaper but will take much longer.
As far as a trip back is concerned if you're leaving from LaGuardia on a weekday you should plan at least 1-1.5 hours to get to the airport (as of late traffic has increased in the city).
Upvote:3
I live right near Penn Station. This is how I do it.
I take the the Long Island Railroad (LIRR) from Penn to Woodside. That's a 15-minute journey, max, and the trains leave about every 20 minutes, max. If you buy a ticket before you get on the train, it's about $8.
Then, I take the LaGuardia link from across the road at Woodside ($2.75, but you have to buy it in advance using the machine thingie at the bus stop). That's about another 20 minutes. It runs 24 hours a day, 7 days a week.
If things are dire, I take an Uber or whatever car-service from Woodside. There are usually some waiting. The important thing is that the train gets you to the other side of the river and saves oodles of time. Timing it well, I've done this trip in 45 minutes, but I wouldn't rely on that.
For Newark, I take New Jersey Transit to Newark Airport from Penn, and then Air Train.
For JFK, the LIRR to Jamaica and AirTrain.
I've stopped taking taxis to the airport at all, because mass transit is always, always, faster.