|Total Coins||Coins from Enemies|
Every main course in Super Mario 64 has a hidden Power Star that involves you collecting 100 coins. Upon collecting the 100th coin, the Power Star will spawn right then and there, so you want to do a tiny bit of planning and not have it appear in the middle of the air or too high up that you might not be able to grab it. Also, when you collect the star, you will not be thrown out of the course, so you can go collect a normal star in the process. Thus, it’s a good idea to try and plan your 100th coin, so it makes the star a lot easier to get. Another thing to consider is which normal star to attempt collecting 100 coins, as there are some differences (some of which are major in later stages) in them.
Note: Every major course will have 8 Red Coins, which equates to 16 regular coins, so you should always take that into consideration.
Tip: You probably want to use any star past the second one, as this makes a Koopa Troopa spawn, which can yield a Blue Coin that’s worth five normal coins.
When you begin the stage, you should see some boxes in front of you, by the wooden signs. The small one can be picked up and breaks upon hitting a flat wall, while simply attack the big ones will break those. The small box contains three coins, while one of the big ones has another three coins (6). There are six enemies on the ground level, including the Goombas and Bob-Ombs, which will yield six more coins (12). Underneath the first bridge you cross is five coins that you might not see due to the camera (17). In the area past the first bridge and before the second bridge, you have three Red Coins, plus a number of enemies, including the Koopa Troopa, so you can add another 18 coins to that total (35).
At this point, in order to avoid having the 100-coin star pop up in the air, it’s best to go to the floating island now and it’s highly recommended you have the [Wing Cap] unlocked for this. There is the Red Coin on the floating island, too (37). Remember the coin rings you had to fly through during Mario Wings to the Sky? Well, there’s a total of 45 coins in the air, so that will add a lot to your total. You don’t need them all, since there’s more than enough to get the 100 coins needed, but you should grab at least 15-20 coins here (82 total, but recommended 52-57).
Return to the ground and head past the second bridge, where the two Red Coins are together. In addition to those, there’s also three Goombas here, but you will also find secret coins here. Each of the wooden poles here can be run around a few times and if done right, they will spit out five coins. With four poles here (and the one holding the Chain Chomp), you can get another 25 coins. Combine that with the above coins in this paragraph, you can add (recommended 84-89; total 114). In the slightly elevated area, you have another small box you can throw for three more coins (recommended 87-92). There’s another four Bob-Ombs here, as well as eight coins around the one flower patch (recommended 99-104).
Underneath the bridge leading to the mountain path, you have another Bob-Omb, as well as another Red Coin (recommended 102-107). As you start up the mountain path, you will find another Bob-Omb by the one cannon, plus you can slide down to get the Red Coin on the hill (recommended 105-110). The final set of coins will be near the cannon firing water bubbles, with there being one last Bob-Omb. Five coins will be next to that cannon and another five next to the cannon you can use (recommended 116-121). Once you get the 100-coin star, grab any other one if you haven’t gotten those, or save your game when prompted and exit the stage via the + Button.