Should I use a travel agent for multi-city South American routes?

Only if your itinerary involves more than 4 countries. Otherwise, the multi-city search tools on sites like Google Flights are sufficient and cheaper.

What is the biggest mistake people make booking flights here?

Booking self-transfers with less than 3 hours between flights. International customs in South American hubs can take 90 minutes; always allow for at least 4-5 hours if you aren't on a single ticket.

Booking Multi-City Flights for South America

Use the 'multi-city' search tool on flight aggregator sites rather than booking separate one-way tickets to avoid airline baggage fees and potential cancellation issues. Always prioritize booking directly with the primary airline alliance to ensure seamless connections and luggage transfer.

Use the Multi-City Tool. Go to Google Flights or Skyscanner and select the 'Multi-city' tab. Never book three separate one-way tickets on different airlines; it makes you responsible for re-checking bags and navigating immigration security during self-transfers.
Group by Geographic Proximity. Plan your route linearly (e.g., Lima -> Cusco -> Santiago -> Buenos Aires) to keep flight times under 4 hours. South American flight paths often hub through major capitals; don't try to backtrack between distant countries, as it will double your travel costs.
Check Alliance Coverage. LATAM and Aerolineas Argentinas are members of major alliances. Use your airline alliance (Oneworld or SkyTeam) to book the entire string of flights; this guarantees that if one flight is delayed, the airline is responsible for rebooking the next leg.
Verify Luggage Rules. Check if your ticket includes checked baggage. Budget carriers in South America (like JetSmart or Sky) are aggressive with weight limits (often 15kg-20kg). Buying baggage at the airport is 3x more expensive than pre-booking it online.

Should I use a travel agent for multi-city South American routes?: Only if your itinerary involves more than 4 countries. Otherwise, the multi-city search tools on sites like Google Flights are sufficient and cheaper.
What is the biggest mistake people make booking flights here?: Booking self-transfers with less than 3 hours between flights. International customs in South American hubs can take 90 minutes; always allow for at least 4-5 hours if you aren't on a single ticket.