What to expect
Booking the flight is the easy part. The useful question is what happens after landing. LATAM markets Lima–Iquitos; check the actual departure, baggage and total fare for your date. Share the flight details with your accommodation or trip organiser before committing to a tight river departure.
How it fits into a journey
For a late arrival, I would sleep in Iquitos first. Have the provider confirm any proposed same-day onward transfer.