Military parades and celebrations will celebrate the birth of the new nation on Saturday in front of dozens of visiting world leaders.
But when that party ends, South Sudan must face grim realities: It will be one of the most underdeveloped countries on the planet, only 15 per cent of its citizens can read and fears of renewed conflict abound.
South Sudan's successful independence drive was made possible by a 2005 peace deal between Sudan's north and south.
Last January, former guerrilla fighters shed tears as they cast votes to break away from the control of the Khartoum-based north.
Among those who cast ballots were some of the 3800 war orphans known as the LostBoys of Sudan, who ran away from war and were taken in by communities in the United States.
In the southern capital of Juba this week, the Republic of South Sudan's new national anthem blared from mobile phones.
"It took a combination of bullets and ballots to attain our hard-earned independence," reads a new sign next to a main intersection in Juba.
Albino Gaw, a member of a minority tribe who works for the government in Juba, said he's excited about the south's independence. The 30-year-old former child soldier said he's pessimistic though about how much work lies ahead.
"The day will be good but people are expecting something more than we've gotten in the past five years," he said. "A lot of work needs to be done by the government. Otherwise things will be like they were before."
World's newest capital emerges from ruins
The world's newest capital, the Nile River city of Juba, was war-ravaged ruins six years ago, when the 1983-2005 north-south civil war ended.
It was the second war between the mostly Arab north and the south, where traditional African religions and Christianity are practiced.
Now the presidential motorcade is practising its run through the city for Saturday afternoon, when world leaders will watch South Sudan President Salva Kiir host the country's inauguration.
UN Secretary-General Ban Ki-moon will attend, as will former US Secretary of State Colin Powell, US Ambassador to the UN Susan Rice and General Carter Ham, commander of the US Africa Command.
Sudan President Omar al-Bashir, a deeply unpopular man in Juba, is also expected to attend.
Violence continues over oil
Despite the excitement, South Sudan is saddled with problems.
Violence - from cattle raids and rebel battles - has killed nearly 2400 people this year, the UN says.
Seven different rebel militias operate in the south.
More ominously, troops from north and south Sudan are facing off in the contested region of Abyei.
Fighting between the north and forces loyal to the south is raging in Southern Kordofan, a state that lies in the north.
A major undercurrent is fight for the oil that lies near the north-south border - oil that South Sudan gains and Khartoum loses, though for now the south's crude can reach the world market only by moving through the north's pipelines.
Despite the south's oil wealth, the region has only about 350 kilometres of paved road.
In an advisory sent out this week for the independence celebration, the government reminded incoming guests that Juba doesn't have any credit card processing machines.
Region "one of most underdeveloped on the planet": UN
Lise Grande, who leads the UN's humanitarian operations in South Sudan, says the region is "one of the most underdeveloped on the planet".
Only 15 per cent of the population can read. Most live on a $US1 a day. Education and health facilities are sorely underdeveloped.
"You don't get the kind of statistics you have in Southern Sudan if you're not dealing with years of marginalisation," Grande said.
"It is their legacy. It is the price that these people have paid."
Still, Zach Vertin of the Brussels-based International Crisis Group says there is reason to be "cautiously optimistic" about the years ahead for the six-year-old government.
It had just two employees when it started - the president and vice president - but now runs 32 ministries, 17 commissions and 10 state-level governments.
The young government faces the massive challenges of reforming its bloated and often predatory army, diversifying its solely oil-based economy, and deciding how political power will be distributed among the dozens of ethnic and military factions.
The government must also begin delivering basic services like education, health services, and water and electricity to its more than 8 million citizens.
Grande said the problems South Sudan faces are "bigger and harder than what any other country in Africa faced" when most nations on the continent gained independence from the colonial powers in the 1960s.
On top of that, the prospect for a return to all-out war between north and south seems higher than it's ever been since the signing of the 2005 peace deal.
More than 100,000 people were displaced in May after the northern army seized the disputed border area of Abyei, and activists fear an ethnic cleansing of the black African Nuba people is under way in Southern Kordofan.
The hostilities dashed hopes that the two governments could reach a deal over unresolved north-south issues related to the peace deal before Saturday, including oil-sharing arrangements and the final demarcation of the border.
A draft constitution was passed this week that lays the groundwork for the president and legislature, who were elected in April 2010, to serve out their five-year terms.
The legislature's few opposition members are unhappy with the draft, but it now serves as an interim constitution until the first multiparty elections are held.
In a sign of the internal political discord South Sudan faces, security forces arrested an opposition leader in parliament and everal others on Thursday after they held a news conference in which they voiced opposition to the new draft constitution, said Lam Akol, chairman of the SPLM-Democratic Change party.
On Saturday at least, politics will be on the backburner. During times of celebration in the south - at weddings or on Martyr's Day - gunshots ring out, symbolic of the history of violence and the fact many civilians own weapons.
The south's information minister is predicting a less violent entry into statehood.
As the clock reaches midnight and the calendar turns to July 9 on Saturday, he said, the only thing to be heard will be "church bells ringing, the beating of drums and women ululating."
