1 week in CR, with 2 teens, reasonable itinerary.

Hi Frida, Keep in mind that the airport is really in a town called Alajuela which is nicer and easier to navigate than downtown San Jose. I took a day trip, local bus from there up to Volcano Poas. If it is clear in the morning you can see down into the crater. I don't believe Arenal is active either but I might be wrong. I would spend your entire time on the Caribbean Coast. There are some great natural parks and in Cahuita the Monkeys and sloths live right above your cabin! You don't really have enough time to do both coasts. I wouldn't waste any time in San Jose at all. As I said there are some sights from Alajuela if you want to pend a night there. It is best to stay there your first night and your last night so you will be sure to catch the plane

Dump the rental car, no need for it. Spend the extra money on shuttles and tours.
Agree with greggo, less time in San Jose the better.

Recommend staying in Alajuela your first night, nice small walking town only a few minutes from the airport.

I'd arrange before you land or have the hotel operator get a private driver and visit Poás Volcano, it's OK, try and see it around 9am before all the clouds come in then head to La Fortuna. Arenal is not active but what the heck it's still a volcano, lots of stuff to do including water falls. Rent a car in La Fortuna for the day if you need to. Then hit the Caribe coast.

Maybe try:

Dec. 17th 1 - night in Alajuela
18-19 - N - 2-3 - Private drive to La Fortuna via Poás Volcano for a couple hours.
20-21 - N - 4 -5 Tortuguero http://www.tortuguerovillage.com/
22- 23 - N - 6-7: Cahuita and it's great NP.
24 - 25 - N - 8-9 Puerto Viejo - Last full day Raft the Pacuare River ( perfect for beginners ) they'll drop you off back in Alajuela.
26 - 10th day - fly home

It's Christmas Day! does tourism work?

If a buck is to be made they'll be open, think.

Thank you greggo and hermosajoe for your input. Super appreciated!
Will consider all the suggestions. Questions:
Is driving any special challenge in CR? I am reading the distances are 3 1/2 hours sometimes less. For a family of 4 it may be less expensive for us than taking shuttles. Am I mistaken here?
Also I read it's green season in the Caribbean region. Is it really rainy in December there?
Thanks so much!
Frida

I think the only challenge in renting a car is theft or driving at night. I think Motoman can help you with that. I think Joe means that you can get the bus to the Caribbean Coast for about $10 each and then take local buses or rent bikes when you get there. If you go to the turtle place you can't bring a car anyway. December is the beginning of the dry season but you shouldn't have to ask yourself why it is raining in a rain forest. The animals and plants love it!

Thanks greggo! Yeah, I get the rain forest... sunny days and late afternoon showers... I'm a tropical woman. The idea is to understand if the pacific coast tends to be dryer than the caribbean coast in December. After some research, it seems to be the case. I'm still working on the best/easiest/most relaxing itinerary for such a short trip with family.
Thanks for the help.

Driving is no major issue, the locals drive crazy and don't drive at night. But no big deal.

If you go La Fortuna and the Caribe no need to rent a car. You really don't want/need a car on the Carbe side, all the distances are short and that's why God invented taxi's.
Tortuguero = No cars allowed.
Cahuita = All walking, Small town and easy walk to the NF and beaches.
Puerto Viejo = walking and bike riding.
I'm sure it's cheaper overall to shuttle/private driver/taxi and leave the driving to some one else then to rent a car for 10 days.

The water from above in CR is warm and no big deal. It's why it's green on the Caribe side and won't effect you vacation.

You only have 8 days so I wouldn't spend time in San Jose.

The Caribbean coast can be wet in December. We were told (and you confirmed you know this already) mornings are often nice and showers can start late afternoon or rain falls overnight. Arenal should get less rainy by the time you are there but sometimes December is still rainy there as well.

Volcano Arenal can be covered in clouds so you have to be a bit lucky to see it. The volcano is not active right now but it is still a beautiful volcano. You can hike, see waterfalls, relax in hot springs and there are lots of adventure activities.

I love the Caribbean coast. Beautiful wild natural beaches bordered by rainforest and lots of wildlife. The National Park in Cahuita is amazing. South of Puerto Viejo we stayed in Manzanillo, a small village with a wildlife refuge.

You could go to Tortuguero by bus/boat, stay a full day, take the scenic boat ride to Moin, bus/taxi to Limon and bus to Cahuita. A full day there. A bus from Cahuita to Puerto Viejo takes 30 minutes. You could rent bikes and bike to Manzanillo, exploring on the way. The rafting company would pick you up in Puerto Viejo, take you rafting and bring you to Arenal. You would have two days left there.

I would point out that there is not a active volcano with lava flow. The Arenal area is once with a lot of activities and fun for a family with children. That said, I agree with above if you want to make it easy on yourself and an your budget, with just 9 days, head to the caribe side, and focus on Tortuguero Canals and Rainforest, Cahuita NP and beaches south of Pt Viejo...

Your plan to start by going up to Arenal via bus in the morning, then after 2 nights, take a shuttle transfer to La Pavona for boats to Tortuguero. The boat to Moin and taxi hire to Cahuita. Beaches then Raft Rio Paquare, or bus direct back to SJ is good.

You will need or have issues with beach reservations Xmas week...thats a tough one..