There are no F lounges--don't think IB has any 3-class service. I've been to the Velazquez lounge in T4-S (Satellite), and it is very nice. I was able to get an ethernet cable from the front desk to sync up my email (or bring your own).

The IB lounges are called VIP Lounges. The gate keepers are much friendlier than the BA Dragons...and a boarding pass seems sufficent for entry as an Emerald or Sapphire status holder.

Definately will be worth a visit.

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There is one VIP lounge in T4:

The DALI lounge . is located on Level 2. This lounge is to be found just after the security controls (both the conventional or Shuttle service controls).
It has been designed for passengers on domestic flights, Puente Aéreo or flying to Schengen destinations.


There are two VIP lounges in T4S:

VELÁZQUEZ lounge is in the central area on Level 1, beyond the shops and restaurants.
It is for international, non-Schengen, passengers
The GOYA is on Level 0, beyond the lift doors on the right-hand side (near gates S)..
It is for passengers on Schengen and domestic flights that operate from T4S