No, it protects you depending upon the SPF rating of the sunscreen. Even the highest-rated sunscreen needs reapplication every two hours. Sunscreen is effective at protecting skin during an initial period of intense UV radiation. Golfers often forget to reapply sunscreen when playing for long hours.
Therefore, it should be reapplied during the course of the game. The sunscreen may come off with sweat, which is why you should reapply your sunscreen at least once or twice during the different game rounds.