The Dutch coach will lead his country in North America this summer and is optimistic that Oranje can have a strong tournament, even if they are not "outright favourites" for glory.
Koeman told World Soccer magazine: "As the Dutch national team, we always enter a tournament to win it. How realistic that is remains to be seen.
"We aren't the outright favourites, like countries that can choose from a much larger pool of top-tier players, but I firmly believe in the quality of our players and the strength of this squad.
"If we stay fit, if everything clicks, and if things go our way at the right moments – which is always necessary at a major tournament – then it could be a fantastic World Cup for us.
"At the same time, the focus is on the short term: a good start, progressing through the group stage, and letting confidence grow. That is ultimately the foundation for success."
The Dutch will face Japan, Sweden and Tunisia in Group E and Koeman is expecting difficult games against all three opponents.
The former Barcelona coach said: "Sweden showed in the play-offs that they deliver when it truly matters... Japan, whom we face in our opening match, are a very fit and disciplined side with several high-quality players. At the last World Cup, they won their group ahead of Spain and Germany – that alone speaks volumes.
"Tunisia might be less familiar to many people, but African nations have been getting stronger for years, and their qualification campaign proved that they are very hard to score against. We must be at our best from the very first match to get through."