LK
Lasse
Koslowski
ASSISTANT REFEREE · 29 appearances
Germany · UEFA

Lasse Koslowski

🚩Germany assistant referee · 7 competitions

Lasse Koslowski is a Germany football assistant referee. They have officiated as assistant referee and fourth official. In total they have 29 tracked match appearances across 7 competitions, broken down as 28× AR, 1× 4th Official. Most-worked competitions include Champions League, Europa League, UEFA Europa Conference League, UEFA Youth League, FIFA WC European Qualifiers and UEFA Europa League Play-Off Round (First Legs). This profile is built from official match-appointment data.

Career Stats

7 comps
29
total appearances
28
Asst. Ref
1
4th Official
Domestic 0International 29

Top Competitions

9
Champions League
2025/26, 2023/24 +1
8
Europa League
2025/26, 2021/22
6
UEFA Europa Conference League
2025/26, 2023/24
2
UEFA Youth League
2019/20
2
FIFA WC European Qualifiers
2025/26
1
UEFA Europa League Play-Off Round (First Legs)
2025/26

Season-by-Season Activity

'19/20
1
'21/22
2
'23/24
4
'25/26
13
AR4th Official
SeasonTotalAR4th
2025/261313—
2023/2444—
2021/2222—
2019/201—1
99—

Career Milestones

Career-firsts tracked in our database.

First tracked match21/10/2019
RB Leipzig v FC Zenit
UEFA Youth League
First international match21/10/2019
RB Leipzig v FC Zenit
UEFA Youth League
First Champions League match19/10/2021
Club Atlético De Madrid v Liverpool FC
Champions League

Match Activity

20 matches · 5 years
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
M
W
F
Role:ARARNo match
🏅

Top 19% among Germany officials

Peer Benchmark

Match Count81%
Seasons Active77%
Competitions82%

Median in Germany: 11 matches · 1 season

Recent Matches

12Mar2026
Europa League
Bologna FC 1909vsAS Roma
assistant2
19Feb2026
Europa League
Pfk Ludogorets 1945vsFerencvárosi TC
assistant1
28Jan2026
Champions League
Páfos FCvsSK Slavia Praha
assistant1
10Dec2025
Champions League
Club Brugge KVvsArsenal FC
assistant2
26Nov2025
Champions League
Sporting CPvsClub Brugge KV
assistant1
Show all 29 matches →

Least-Officiated Teams

Clubs in their current competition, ordered by how seldom this official has worked their matches.

Each number = matches officiated involving that club · 0× = never officiated them

  1. 11. FC Slovácko1×
  2. 2AS Saint-étienne1×
  3. 3AS Saint-étienne Loire1×
  4. 4Aek1×
  5. 5Alanyaspor1×
  6. 6Apóel FC1×
  7. 7Apóllon Limassol FC1×
  8. 8Aris Thessaloniki FC1×
  9. 9Barry Town United FC1×
  10. 10Beitar Jerusalem FC1×

Top Destinations

  1. 1Alkmaar
    1×
  2. 2Almaty
    1×
  3. 3Bialystok
    1×
  4. 4Birmingham
    1×
  5. 5Eindhoven
    1×
  6. 6Ghent
    1×
  7. 7Glasgow
    1×
  8. 8Helsinki
    1×
  9. 9Istanbul
    1×
  10. 10Kopavogur
    1×
  11. 11Leipzig
    1×
  12. 12Ljubljana
    1×
  13. 13Madrid
    1×
  14. 14Milan
    1×
  15. 15Ruzomberok
    1×

Venues Visited(16)

Stadiums Lasse Koslowski has officiated at. Filter by competition or season to focus the map.

No mapped venues with coordinates for this filter.

16 venues · 16 matches

AlkmaarAlkmaar1 match
AlmatyAlmaty1 match
BialystokBialystok1 match
BirminghamBirmingham1 match
EindhovenEindhoven1 match
GhentGhent1 match
GlasgowGlasgow1 match
HelsinkiHelsinki1 match
IstanbulIstanbul1 match
KopavogurKopavogur1 match
LeipzigLeipzig1 match
LjubljanaLjubljana1 match
MadridMadrid1 match
MilanMilan1 match
PlzenS tadion mesta Plzne1 match
RuzomberokRuzomberok1 match

Other Germany Officials

🇩🇪VAR
BD
Bastian
Dankert
178 matchesiREFEREE
🇩🇪VAR
CD
Christian
Dingert
150 matchesiREFEREE
🇩🇪Referee
HO
Harm
Osmers
98 matchesiREFEREE
🇩🇪Fourth Official
DS
Daniel
Schlager
92 matchesiREFEREE
🇩🇪Referee
SS
Sascha
Stegemann
91 matchesiREFEREE
🇩🇪VAR
MF
Marco
Fritz
90 matchesiREFEREE
All Germany officials →

Career Events

Career events (UEFA courses, awards) will appear here when available.

Season Reports

2025/26 (13)2023/24 (4)2021/22 (2)2019/20 (1) (9)

Frequently Asked Questions

What is Lasse Koslowski's primary role?▾

Lasse Koslowski is a Germany football assistant referee, and has also worked as fourth official.

How many matches has Lasse Koslowski officiated?▾

Lasse Koslowski has 29 tracked match appearances across 7 competitions (28× AR, 1× 4th Official).

Which competitions does Lasse Koslowski work in?▾

Lasse Koslowski has most often officiated in Champions League, Europa League, UEFA Europa Conference League, UEFA Youth League, FIFA WC European Qualifiers and UEFA Europa League Play-Off Round (First Legs).

Is Lasse Koslowski a FIFA referee?▾

Lasse Koslowski is not currently recorded as a FIFA badge holder in our data.