Nicaragua for 3 weeks

most of this post is dependent on other things and cant really be answered based on the info tht you have given.

What do you consider the carribean coast? For most people that means the bluefields/corn islands area. And there are no roads connecting the pacific side to the carribean. So you take a 6 hour bus to rama, and then take a boat up the river for a few more hours to bluefields. From there you can take different small boats to pearl lagoon, kukra hill, corn islands or the surrounding areas.
Alternatively you can fly there to bluefields from managua round trip for less than 100 bucks, or round trip to corn islands for less than 150.

There is also the northern carribean coast, puerto cabezas, which is much less traveled. There is a road there that isnt in great condition, so its a lengthy 12+ hour bus trip from Managua. Less if you are already on the way, like Matagalpa and catch a passing bus (youll have to ask around in the town when the buses pass through as they arent super frequent).

As for having enough time, it depends. The carribean coast is not a day trip, but if you fly, or even take land travel, you could see it in just a few days. If you like to take things slower and experience the culture, and see multiple places, or do up river and see native villages, etc. You will want at least a week for that stuff.
As for fitting that in with your other things, thats also dependent on what you want to do there. Some people see Leon in a day trip, others can spend weeks there. Same with Granada. So it all depends on what you want to do, or what kind of trip you would like to have.

Also, unless you are going to Corn Islands, or going to really rough it and try to go to cayos miskitos, etc. You may wanna look up info about the carribean beaches of Nicaragua. They probably arent quite what you are thinking of in your mind. Most of the coast is undeveloped jungle and very muddy, etc. Not much for white sand, teal water, super clean areas.
If you want beach experiences, the pacific has miles of open empty beaches. The waters not as calm, but its a beach experience.

Hello!
I am very much in the same boat (or lack there of...) that you are. My travel time is limited and I'd like to see the Caribbean coast. I'd like to see both the area of Puerto Cabezas and Little Corn Island. I am quickly realizing that transportation on that side of the country is either time consuming or expensive. Like you, there are other parts of Nicaragua I'd like to explore.
So far, this is what I've considered-
Flight to Puerto from Managua- spend 3 or so days there. Then from Puerto to Bluefields by airplane. This is where the challenge enters. Boats from Bluefields to Corn Island run on a limited basis (usually only Wednesday from what I read) I am trying to avoid flying back through Managua for time and financial reasons. You can take a bus between Managua and Bluefields/El Rama, but again scheduling is key.
Please let me know what you find out and decide. What else is on your agenda?
Thanks!

Also, check out:
rightsideguide.com

#2.....Why are you going to Puerto? Nothing there for you. This is a bad idea and a waste of your vacation time.

If the original poster wants beach time, them you want either Big or Little corn. That has the Caribbean Sea which is by far the best for just beaching it. Some beautiful spots with no one on the beach. Good snorkeling, good seafood, cheap accommodations, what more do you want. The airfare from Managua is about $170 round trip. Taking the boat is an option but when you factor in the time, the buses or shuttles, the rooms you may need and the cost, it isn't that much more for the flight and it is MUCH faster.

If you want to see the caribean side is faster to take a flight of course. But you can go by bus up to Pear Lagoon. The bus starts from El Rama. In Pear Lagoon you can visit some villages around and maybe you will find some other travellers to share a boat to the Cayos/keys (small tropical islands) From Pear Lagoon you can also take a boat to Bluefields, it takes 45 minutes and from there to Big Corn Island.

If you are in Leon you can visit in a day trip different beaches or volcanoes including trekking.

saludos Josecito

That's Pearl Lagoon. Not a lot there but good for a day or two. Better on the islands.