TAMARINDO, Costa Rica, (Reuters) - Once-bustling  construction sites on Costa Rica’s Pacific coast are lying  silent as a real estate boom fueled by tourists and U.S.  expatriates slumps due to the global financial crisis.

At a dozen building sites around the picturesque Tamarindo  resort town, where workers once crawled up and down hulking  concrete structures, now only security guards stand vigil in  the midday tropical sun.

The site is part of a series of beaches known as Costa  Rica’s “Gold Coast,” which became one of Central America’s  hottest property spots when a local airport began handling  international flights six years ago.

Now the beach, normally crowded at this time of year, Costa  Rica’s busiest tourist season, is half empty as cash-strapped  travelers opt to stay at home.

Tourism is Costa Rica’s No. 1 source of foreign exchange  earnings, so any dip can have a major economic impact on the  country, also known for its eco-lodges in tropical jungles. “We didn’t expect this to happen, no one saw the crisis  coming,” said developer Guillermo Cubas, whose six-unit Brisas  del Monte condominium stands idle.

Cubas’ bank cut off his credit line last year when Costa  Rica’s banking system suffered a liquidity shortfall amid the  turmoil in global markets.    Guanacaste province, where Tamarindo is located, is  reporting a drop of nearly a third in hotel occupancy rates for  the first two months of 2009 compared to 2008, according to  Pablo Solano, the head of the national hotel chamber.