From Warsaw Chopin Airport

By train

Step 1

Train from: WARSZAWA LOT. CHOPINA [1]
To: WARSZAWA CENTRALNA
Price: about 6PLN (student discount: 51%)
Timetables:  SKM (Fast Urban Railway) [2], Mazowieckie Railways [3]
Travel time: about 25 min

Step 2

Train from: WARSZAWA CENTRALNA
To: SOSNOWIEC
Price: about 50-150PLN (student discount: 51%)
Timetables: PKP [4]
Travel time: about 3 hours

By bus from Airport to main railway station of Warsaw and later by train to Sosnowiec

Step 1 - Day route by bus #175 [5]

Bus from: LOTNISKO CHOPINA [1]-PRZYLOTY 02 (bus station near to arrivals terminal)
To: DW. CENTRALNY 01 (bus station near to Warsaw main railway station)
Price: about 5 zł (student discount: 51%)
Timetables: ZTM [5]
Travel time: about 25 min.

Step 1 - Night route by bus #N32 [6]

Bus from: LOTNISKO CHOPINA [1]-PRZYLOTY 02 (bus station near to arrivals terminal)
To: DW. CENTRALNY 14 (bus station near to Warsaw main railway station)
Price: about 5 zł (student discount: 51%)
Timetables: ZTM [6] 
Travel time: about 25 min.

Step 2

Train from: WARSZAWA CENTRALNA
To: SOSNOWIEC
Price: about 50-150PLN (student discount: 51%)
Timetables: PKP [4]
Travel time: about 3 hours

From Warsaw Modlin Airport

By bus and train

Step 1

Bus from: MODLIN LOTNISKO
To: MODLIN
Travel time: about 10 min

Step 2

Train from: MODLIN
To: WARSZAWA CENTRALNA
Travel time: about 45 min

Price of the route: about 20 zł (student discount: 51%)
Timetables: Mazowieckie Railways [3]

Step 3

Train from: WARSZAWA CENTRALNA
To: SOSNOWIEC
Price: about 50-150PLN (student discount: 51%)
Timetables: PKP [4]
Travel time: about 3 hours