The timescales of transport from the surface to the tropical tropopause layer (TTL) was studied using the Lagrangian transport model Flexpart. The model was driven by the ERA-Interim reanalysis from the European Center for Medium-Range Weather Forecasts (ECMWF). Trajectories were released each month in the period 1. June 2002 - 1. May 2013 at 15 km and 17 km over the whole tropics and simulated 90 days backward in time. The age of air at 15 km and 17 km relative to the last contact with the boundary layer (BL) was computed using a constant BL-height of 1 km above sea level. The aim of the study was to give a detailed description of the tropospheric age of air in the TTL, mainly motivated by the importance of transport timescales for the entry of short-lived compounds to the stratosphere. Several sensitivity studies were carried out. The most important of these were the sensitivity to the use of the convection scheme in Flexpart. In the run without the convection scheme, the median age at 15 km was 17 day longer, and at 17 km 25 days longer, than in the runs using the convection scheme. In particular, the fraction of the air at 17 km younger than 10 days decreased with an order of magnitude, from 11.1 % to 0.9 %. For 30˚S - 30˚N as a whole, the median age was 26 days at 15 km and 50 days at 17 km. A seasonal cycle in the age was found at both altitudes. The seasonal cycle was most pronounced at 17 km, where the median age varied by ∼14 days during the year, being highest in August and lowest in May. At both altitudes, the air was younger near the main convective areas in the tropics, such as the Intertropical Convergence Zone (ITCZ), with less young air approaching the subtropics. The air was particularly young above the tropical western Pacific; the median age there was only 16 days at 15 km and 30 days at 17 km. The air at both 15 km and 17 km was found to originate from the BL above the main convective regions in the tropics. In particular, the West and Central Pacific stood for 40-50 % of the BL-origins. The age decreased over the period, both at 15 km and 17 km. The decrease in the annual median age during 2003-2012 was 2.0 days per decade at 15 km and 9.7 days per decade at 17 km (for 30˚S - 30˚N). Much of this decrease appeared to have taken place around 2009. Interannual variability in the age above the tropical Pacific in December-February (DJF) was found to be related to the El Niño-Southern Oscillation (ENSO). The air was younger above the Pacific in El Niño and older in La Niña. A shift in the BL-origins above the Pacific ocean, eastward in El Niño and westward in La Niña, was also found.