1. **State the problem:** Alonzo swims 3000 meters each week. We need to convert this distance into kilometers. 2. **Recall the conversion formula:** $$1 \text{ kilometer (km)} = 1000 \text{ meters (m)}$$ This means to convert meters to kilometers, divide the number of meters by 1000. 3. **Set up the conversion:** $$\text{kilometers} = \frac{\text{meters}}{1000}$$ 4. **Substitute the given value:** $$\text{kilometers} = \frac{3000}{1000}$$ 5. **Simplify the fraction:** $$\text{kilometers} = \frac{\cancel{3000}}{\cancel{1000}} = 3$$ 6. **Interpret the result:** Alonzo swims 3 kilometers each week. **Final answer:** $$\boxed{3 \text{ kilometers}}$$