diff --git a/app/features/admin/routes/admin.test.ts b/app/features/admin/routes/admin.test.ts
index 528430062..2d23a27b8 100644
--- a/app/features/admin/routes/admin.test.ts
+++ b/app/features/admin/routes/admin.test.ts
@@ -124,7 +124,7 @@ describe("Plus voting", () => {
 	test("combines leaderboard and voting results (after season over)", async () => {
 		vi.setSystemTime(new Date("2023-11-29T00:00:00.000Z"));
 
-		await dbInsertUsers(2);
+		await dbInsertUsers();
 		await PlusVotingRepository.upsertMany([
 			voteArgs({
 				score: 1,
@@ -177,7 +177,7 @@ describe("Plus voting", () => {
 	test("ignores leaderboard while season is ongoing", async () => {
 		vi.setSystemTime(new Date("2024-02-15T00:00:00.000Z"));
 
-		await dbInsertUsers(2);
+		await dbInsertUsers();
 		await PlusVotingRepository.upsertMany([
 			voteArgs({
 				score: 1,
diff --git a/app/features/team/actions/t.server.test.ts b/app/features/team/actions/t.server.test.ts
new file mode 100644
index 000000000..f548fcef8
--- /dev/null
+++ b/app/features/team/actions/t.server.test.ts
@@ -0,0 +1,30 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { dbInsertUsers, dbReset, wrappedAction } from "~/utils/Test";
+import { action as teamIndexPageAction } from "../actions/t.server";
+import type { createTeamSchema } from "../team-schemas.server";
+
+const action = wrappedAction<typeof createTeamSchema>({
+	action: teamIndexPageAction,
+});
+
+describe("team creation", () => {
+	beforeEach(async () => {
+		await dbInsertUsers();
+	});
+	afterEach(() => {
+		dbReset();
+	});
+
+	it("prevents creating a team with a duplicate name", async () => {
+		await action({ name: "Team 1" }, { user: "regular" });
+		const res = await action({ name: "Team 1" }, { user: "regular" });
+
+		expect(res.errors[0]).toBe("forms.errors.duplicateName");
+	});
+
+	it("prevents creating a team whose name is only special characters", async () => {
+		expect(action({ name: "𝓢𝓲𝓵" }, { user: "regular" })).rejects.toThrow(
+			"status code: 400",
+		);
+	});
+});
diff --git a/app/features/team/routes/t.$customUrl.edit.test.ts b/app/features/team/routes/t.$customUrl.edit.test.ts
new file mode 100644
index 000000000..cd4f4c8a3
--- /dev/null
+++ b/app/features/team/routes/t.$customUrl.edit.test.ts
@@ -0,0 +1,59 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { dbInsertUsers, dbReset, wrappedAction } from "~/utils/Test";
+import { action as teamIndexPageAction } from "../actions/t.server";
+import { action as _editTeamAction } from "../routes/t.$customUrl.edit";
+import type { createTeamSchema, editTeamSchema } from "../team-schemas.server";
+
+const createTeamAction = wrappedAction<typeof createTeamSchema>({
+	action: teamIndexPageAction,
+});
+
+const editTeamAction = wrappedAction<typeof editTeamSchema>({
+	action: _editTeamAction,
+});
+
+describe("team creation", () => {
+	beforeEach(async () => {
+		await dbInsertUsers();
+	});
+	afterEach(() => {
+		dbReset();
+	});
+
+	it("can't take another team's name via editing", async () => {
+		await createTeamAction({ name: "Team 1" }, { user: "regular" });
+		await createTeamAction({ name: "Team 2" }, { user: "regular" });
+
+		const res = await editTeamAction(
+			{
+				_action: "EDIT",
+				name: "Team 2",
+				bio: null,
+				bsky: null,
+				css: null,
+				twitter: null,
+			},
+			{ user: "regular", params: { customUrl: "team-1" } },
+		);
+
+		expect(res.errors[0]).toBe("forms.errors.duplicateName");
+	});
+
+	it("prevents editing team name to only special characters", async () => {
+		await createTeamAction({ name: "Team 1" }, { user: "regular" });
+
+		expect(
+			editTeamAction(
+				{
+					_action: "EDIT",
+					name: "𝓢𝓲𝓵",
+					bio: null,
+					bsky: null,
+					css: null,
+					twitter: null,
+				},
+				{ user: "regular", params: { customUrl: "team-1" } },
+			),
+		).rejects.toThrow("status code: 400");
+	});
+});
diff --git a/app/features/team/routes/t.$customUrl.edit.tsx b/app/features/team/routes/t.$customUrl.edit.tsx
index a1d719593..f8645376e 100644
--- a/app/features/team/routes/t.$customUrl.edit.tsx
+++ b/app/features/team/routes/t.$customUrl.edit.tsx
@@ -95,6 +95,11 @@ export const action: ActionFunction = async ({ request, params }) => {
 			const newCustomUrl = mySlugify(data.name);
 			const existingTeam = await TeamRepository.findByCustomUrl(newCustomUrl);
 
+			validate(
+				newCustomUrl.length > 0,
+				"Team name can't be only special characters",
+			);
+
 			// can't take someone else's custom url
 			if (existingTeam && existingTeam.id !== team.id) {
 				return {
diff --git a/app/features/team/routes/t.$customUrl.test.ts b/app/features/team/routes/t.$customUrl.test.ts
index 8c74958b8..f69b1b7f6 100644
--- a/app/features/team/routes/t.$customUrl.test.ts
+++ b/app/features/team/routes/t.$customUrl.test.ts
@@ -48,7 +48,7 @@ async function loadTeams() {
 
 describe("Secondary teams", () => {
 	beforeEach(async () => {
-		await dbInsertUsers(2);
+		await dbInsertUsers();
 	});
 	afterEach(() => {
 		dbReset();