There is currently a major reduction in services due to geological problems on the line in the area of Yeovil. From Monday 11th August there will be a two-hourly service from Waterloo to Exeter, and a two-hourly service from Waterloo to Yeovil. (i.e. there's a train west of Yeovil once per two hours).
Correct current times are in on-line booking systems, and SWR have published a full timetable which can be viewed or downloaded here.
This version includes the small amendment made on 1st September.
These changes are expected to last until some time in November.
There is an additional service not shown in the SWR timetable. GWR run a service Monday to Friday from Exeter St Davids to Axminster at 17:48, calling at all stations except Whimple. It returns from Axminster leaving at 18:40 all stations except Whimple to Exeter Central (not St Davids).
Not currently applicable:
You can view or download the current timetable here. The handy pocket timetable from SWR can be viewed or downloaded here.