Condado is easy to reach from anywhere in greater San Juan. From Luis Muñoz Marín International Airport, the standard approach is a taxi — the ride takes 15 to 20 minutes depending on traffic and costs a flat rate to the Condado hotel zone. Rideshares (Uber operates in San Juan) are somewhat cheaper. There is no direct bus from the airport to Condado; connections require changing in Isla Verde or at one of the main bus terminals.
From Old San Juan, the most enjoyable option is to walk: the route east through Puerta de Tierra takes about 30 minutes along the waterfront boulevard and gives a good sense of the geography between the old city and the modern hotel strip. Bus routes 5 and 21 also cover this corridor if you prefer not to walk in the heat. From the cruise terminal in Old San Juan, the same options apply — taxi in 20 minutes, or bus/walk for the more ambitious. Note that Condado has almost no public parking; if you're renting a car, confirm your hotel has parking before you commit to driving.