Costa Rica

I'm not familiar with that park, but we didn't see a whole lot of wildlife at Arenal, although we also didn't do a whole lot of walking there. I loved Arenal. We stayed at Tabacon during "green" season, and it was magical having the hot springs Shangri La area almost to ourselves. We did do a hanging bridges walk and saw a lot of small wildlife--leaf cutter ants, teeny tiny bees, a snake, various birds, poison dart frogs, and one sloth at a distance. There were a number of iguanas at the hot springs, too.

Where we did see more wildlife was in the Manuel Antonio area. We stayed at Arenas del Mar, and they have quite a lot of protected land, in addition to their beach access. We saw (many) capuchins and squirrel monkeys there. We saw sloths and even had a baby sloth come to the ground (to poop) and spend some time on the ground right beside us. We saw various birds. We did a guided night walk and saw red-eyed tree frogs, a false fer-de-lance, red land crabs, scorpion spiders, and I forget what else. We then stayed at Costa Verde (in an old airplane cockpit fuselage turned into a cottage), and we saw even more monkeys--had them on our roof even--had a sloth in the tree outside our window, and saw capybaras, toucans, bats and blue Morpho butterflies. We could hear the howler monkeys at Manual Antonio park next door. We went on a tour in the park and saw more of the same. We went to a canal where there are HUGE iguanas. We went on a boat ride through the mangroves and saw more bats, monkeys, and some waterfowl.
On our way back to San Jose, we stopped and saw red macaws in trees along the coast and giant crocodiles under the Tarcoles River Bridge.

Anyway, based on our experience, I'm guessing you will see more wildlife at the national park than at Arenal, but both are worthwhile. However, we saw the most wildlife at the two resorts we stayed at in the Manueal Antonia area.

When I visited Costa Rica, we stayed near Uvita. We took a day trip to Corcovado which included a boat ride. There was a lot of wildlife, including the beautiful Scarlet Macaws. We rented a car, so from Uvita it was a reasonable drive to Manuel Antonio too. We stayed at the Tikis Village Resort. Very nice!

Thank you so much for your input. I had read about Manuel Antonio park as well.
I had been thinking of combining Corcovado and Manuel Antonio but thought that might be too much beach and maybe the volcano environment would be so interesting too. With only 7 days, I have to fight my urge to cover too much ground.
Thanks

My daughter is going to Costa Rica next week and mentioned some highly rated wildlife rescue sanctuaries including a Jaguar rescue centre.

Ive been both places. Both are great. I suggest corcovado to have option for beach and use warm sea to relax. Are hotels on the seadide
Are also jungle ordinary hostel. Many options of spend time without hiking. Arenal is nice for few days. Walk i to volcano site. Look at łazi g Animals. Relax in natural River hot Springs. Than can go for River trips or just relax.