Airlines are waiving change fees and cancellation penalties through Aug. 26 due to Tropical Storm Isaac.
LIAT and American Eagle canceled several Caribbean flights Wednesday and disruptions are anticipated on Thursday as well, depending upon the storm track.
El Morro Castle in Old San Juan was closed to visitors on Thursday.
Some flooding in low-lying areas of Guadeloupe and Martinique was reported as Isaac moved across those islands late Wednesday.
The National Hurricane Center predicts that Isaac will pass over Haiti and western Cuba early Friday and possibly hit Florida over the weekend.
Follow Gay Nagle Myers on Twitter @gnmtravelweekly.