I am planning a family trip with my 2 daughters ages 7 and 10. We only have 7 days total. Would 3 days in MA and 3 days in Osa be too repetitive?
I am trying to limit driving and plan to fly to Osa.

If you only have a week I would skip MA and fly straight to the Osa. Anything MA has (flora and fauna) the Osa has more of. Except tourists. If you enter the Osa from Puerta Jimenez you have the option of exploring the rest of the gulf.

What time of year are you going? During the high season you can get a flight to Puerto Jimenez from Quepos. The hotel you are staying in can arrange for that flight as it is not a regular flight and therefore not on the posted schedule.

If you are thinking of Drake Bay, you will most likely have to fly to San Jose from Quepos and then to Drake Bay. A private charter would run about $800-$900 one way if you don't want to use the regularly scheduled flights.

Honestly, as much as I love the Osa-I don't go to MA anymore because of the tourists, your daughters might enjoy a combination of Arenal and Manuel Antonio better. Los Lagos is a great place for kids in the Arenal area. It would be about a 5-6hr drive from Arenal to Manuel Antonio (more depending on stop times) but you can stop in Jaco for lunch and at the Rio Tarcoles to see the famous Crocs. A note of caution, do not leave car unattended or out of your sight if at all possible. Theft from cars is a problem in CR-carry all papers and passports with you if leaving the car. The day would not be spent just driving with a couple of these interesting stops.

All of this is just a suggestion because I (we) don't really know your daughters and what kinds of activities they would enjoy. Some kids are better travelers than others and don't need constant entertainment in regards to things to do. Possibly a little more information from you as far as the things you and they might enjoy would help.

Thank you for your comments. We would be going in Feb2005. I am now thinking maybe a few nights at Peace Lodge (horseback ride, and other attractions) and then down to Osa Pen (trying to get a reservation at Bosque del Cabo or other similar lodge)for canopy tour, dolphin watch, guided trails in Corcovado.
What do you think.
Girls are great travelers, but I don't think being in the car for more than 2 hours will work. I was thinking of driving to Peace Lodge, then back to SJ to take a flight to Osa.

Sounds like a good plan. Bosque del Cabo is a wonderful place to stay, but it isn't as convenient to tour Corcovado from there as it is from the Drake Bay side. That is really not a problem because at BDC you'll see tons of wildlife! Many say they see more there than inside the park.