Well, it’s impossible to se whole the island with a bus sightseeing tour in one day. That option is available with an exclusive private VIP tour only and takes at least 12 hours. Therefore, to see whole Tenerife with a cheaper bus sigtseeing excursion you ought to do at least 2 different tous.
One of these bus tours is Teide & West Coast – Bus Sightseeing Tour taking you to Teide National Park, Masca, Garachico, Icod de Los Vinos with its Dragon Tree and another tour is Anaga & Two Capitals – Bus Sightseeing Tour taking you to the actual island’s capital – Santa Cruz de Tenerife, to the former capital extremely rich in architecture La Laguna, endemic jungle in northernmost Anaga peninsula and Taganana village.
These two tours doesn’t cross its ways and it’s important to remember the second excursion to the North of Tenerife you do with Tenerife Host only on Wednesdays and Saturdays while the tour to Teide and West Coast available every day except Sunday.