Asunción City Tour is a receptive operator with its own fleet — sedans up to 52-seat coaches — and guides accredited with SENATUR, working in German, English, Portuguese and Spanish at no surcharge if you ask in advance. That combination is rarer in Paraguay than you would expect, and it is why they turn up on other people's itineraries as the ground handler.
The short one is the panoramic city tour, three to four hours, leaving at 08:30 or 14:30, doing the historic centre, the modern zone and the older barrios. Five hours gets you the Lago Ypacaraí run through San Lorenzo, Itauguá, Ypacaraí, San Bernardino, Areguá and Luque. The Circuito de Oro is the full day, eight hours from 08:30, twelve towns, and they say plainly it is their best seller.
Further afield they run the Jesuit missions as one or two days — San Cosme y Damián first, then Jesús de Tavarangüé and Trinidad — Iguazú via the Itaipú dam as one or two days, and a two-or-three-day Chaco trip that takes in the Pa'i Puku school, Laguna Capitán, Filadelfia with the Jakob Unger museum and Fortín Boquerón, and the Loma Plata co-operative and dairy. There is also an eight-hour "tour étnico" through Villa Hayes to the Toba community at Cerrito and the Maká community nearer the city.
No prices are published. Phones are answered 08:00 to 18:00 local time; the WhatsApp is the booking channel they point you at first.