Three or four companies in Arica regularly offer tours up to Parque Nacional Lauca. The problem is that the most commonly available tour takes place in a single day, which means rushing from sea level to up to 4500m and down again in a short space of time – really not a good idea, and very likely to cause some ill effects, ranging from tiredness and mild headaches to acute dizziness and nausea. In very rare cases the effects can be more serious, and you should always check that the company carries a supply of oxygen and has a staff member trained to deal with emergencies.
Altitude aside, the amount of time you spend inside a minibus is very tiring, which can spoil your experience of what is one of the most beautiful parts of Chile. Therefore it’s really worth paying extra and taking a tour that includes at least one overnight stop in Putre; better still is one continuing south to the Salar de Surire and Parque Nacional Isluga. However, it’s worth noting that the availability of these longer tours can be frustratingly scarce during the quieter low season months.