The answer is yes. However, the needs of elite and professional athletes differ from those of weekend warriors. If you are a serious athlete, do your homework by reading a book such as The Vegetarian Way by Virginia and Mark Messina. Sufficient calcium can be obtained from plant foods. The same is true for iron.
Vegetarians are no more likely to be iron deficient than anyone else.
In fact, vegetarian diets contain more iron than meat-based diets, and vegans have the highest iron intake of all. In a study conducted in Great Britain, researchers found that vegan children consumed twice as much iron as nonvegetarian children. A. Pound for pound, fresh veggies usually cost less than meat. And beans and rice are always cheaper by far. As you change your shopping style, you're likely to find you spend far less on food than you did before becoming vegan.