Road Advisor is right - those are the two best ways - it kind of depends on your budget too. The bus to Puntarenas - then ferry to Paqurea - then bus to Montezuma is way way cheaper and pleasant but more time consuming.
The water taxi from Jaco (Herradura beach actually, just north of Jaco itself ) lands you right in Montezuma in just an hour, but costs around $40. - going this way, choose Zuma tours, they have the best equipment, are licensed and are safety conscious
To get from Montezuma to Tamarindo - same thing - it depends on your budget/time balance.
You can get a shuttle-ferry-shuttle (same shuttle, but you still need to take the ferry)
bus - ferry - bus to Liberia, -another bus to Tamarindo
I have some bus/ferry details if you are interest in those options - the ferry times do change
rent a car, easy driving, I pretty much did your same trip over about 8 days, landed in LIR, drove to Puntarenas, ferry to Montezuma, back across ferry, drove to MA with a stop in Jaco, and then MA to Tamarindo, flew back out of LIR
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